How to Use | Property Investment Analyzer

What this calculator does

This tool answers two different property questions. It does not predict the future, and it does not tell you what to do. It takes the assumptions you enter and works out, arithmetically, what would follow from them.

Buy to Live is for a home you would live in. It compares two paths over a period you choose: buying the property, or renting a comparable one and investing the money you would otherwise have put into buying. Both paths are measured the same way at the same moment, so the comparison is like for like.

Buy to Rent is for a property you would let to a tenant. It works out what the rent produces after the costs of running the property, what is left after the mortgage, what the property is worth at the end, what a sale would leave you with, and what all of that amounts to as a return on the cash you put in.

Before you start

The analysis is only as good as what you put into it. It helps to notice that the inputs are not all the same kind of thing — some are facts you can look up, and some are guesses about the future that nobody can make reliably.

Known values. A real document holds the exact number: the asking price, the mortgage offer, the loan term, the transfer and legal fees, the building's service charge, the property tax bill, an insurance quote, the agent's selling commission.
Market observations. No document holds them, but you can look at the market: what comparable properties rent for, and how long they tend to sit empty between tenants.
Estimates. Only an educated guess is possible: maintenance, renovation, a managing agent's fee. Make the estimate as concrete as you can, then try a higher one and see whether it changes your conclusion.
Future assumptions. Property appreciation, rent growth, investment returns. Nobody knows these. They are not values to get right — they are values to test.

Gather the first group before you begin; the analysis is far more useful with real numbers in it. For the last group, resist the urge to find the one correct figure. Run a cautious case, a middle case and a stronger case, and see whether your conclusion survives all three. If it does, you have learned something durable. If it flips, you have learned that the decision rests on a forecast rather than on the property — which is just as worth knowing.

Buy to Live: the question it answers

"Am I better off buying this home, or renting something similar?" — asked properly, over a period you choose.

Asked carelessly, that question is unanswerable, because renting looks like pure cost and buying looks like building something. The comparison here is deliberately fairer than that. The renter is assumed to invest the money the buyer would have spent: the whole deposit and every one-time purchase cost on day one, and afterwards the monthly difference whenever owning costs more than renting. Both households spend the same amount each month. The only difference is where the money goes.

At the end of the period, the two sides are compared. The buyer's position is measured as if the property were actually sold and the selling costs actually paid, because the renter's investments could be cashed in at any moment and comparing an unsold property's headline value against that would flatter buying.

Rent + invest strategy: The alternative buying is compared against: rent a similar property, and invest the money you would otherwise have put into buying.
Renter investment portfolio: The running value of the money the renter has invested instead of buying.
Analysis horizon: How many years the analysis runs for. Every result is measured at the end of this period.

Buy to Live: filling in the form

The form is grouped in the order the money actually moves: what you are buying, how you are paying for it, what it costs to buy, what it costs to keep, what renting instead would look like, and what selling would cost at the end.

Property

The price of the property itself, the currency everything is entered in, how much you assume the property's value changes each year, and how many years the analysis runs for.

Two of these deserve care. Appreciation is a forecast, and usually the single most influential number in the whole analysis. The analysis horizon is the finish line: the property is treated as sold at the end of it, so the same property can give opposite answers over three years and over fifteen. It is not the same thing as the loan term — you can sell long before the mortgage ends.

Purchase price: The agreed price of the property itself, before any of the extra one-time costs of buying it.
Property appreciation: How much you assume the property's value changes each year, as a percentage.
Analysis horizon: How many years the analysis runs for. Every result is measured at the end of this period.
Currency: The currency every amount in this analysis is entered and displayed in.

Financing

Whether you are borrowing or paying cash, and if borrowing: how much of the price you pay yourself, the annual interest rate your lender quotes, and how many years the loan runs for.

The down payment is what decides the size of the loan — whatever part of the price you do not pay yourself is what you borrow. The form shows both figures in money as you type, so the percentage never hides the actual amount. If you choose Cash, the mortgage fields are switched off, because there is no loan to describe.

Purchase method: Whether you are paying for the property with a mortgage or entirely with your own cash.
Down payment: The part of the purchase price you pay from your own money, rather than borrowing.
Loan amount: How much you borrow: the purchase price minus your down payment.
Mortgage interest rate: The annual interest rate on the loan, as your lender quotes it.
Loan term: How many years the mortgage is scheduled to be repaid over.

Acquisition costs

The one-time costs of buying, paid once at the start: transfer and registration fees, legal fees, renovation, furniture, any fee for arranging the loan, and anything else that does not fit those.

These matter more than they look. They are cash you have to find on day one, they raise the amount every return is measured against, and they are money you would not spend at all if you rented. Leaving them all at zero is the quickest way to make buying look better than it is.

Renovation and furniture are treated purely as costs. Spending on them does not automatically raise the property's value here — if you believe a renovation adds value, that belongs in the appreciation assumption, entered deliberately, rather than appearing on its own.

Transfer and registration fees: One-time official costs of legally transferring the property into your name.
Legal fees: One-time cost of the lawyer or conveyancer handling the purchase.
Renovation costs: One-time money spent on the property after buying it, before it is ready to live in or let.
Furniture and appliances: One-time cost of furnishing and equipping the property.
Mortgage setup costs: One-time fees charged for arranging the loan, such as arrangement or origination fees.
Other initial costs: Any remaining one-time cost of buying that the other fields do not already cover.

Ownership costs

What it costs to keep the property, year after year: the building or estate fee, property tax, insurance, maintenance, and anything else recurring. These continue whether or not the mortgage is paid off.

Maintenance is the one people leave at zero most often. Real maintenance is lumpy — nothing for two years, then a boiler — so an average yearly figure is the practical way to enter it. Zero says the property never needs anything, which no property does.

HOA / common area fee: The recurring charge paid to the building or estate for shared maintenance and services.
Property tax: The recurring tax charged on owning the property.
Insurance: The recurring cost of insuring the property.
Maintenance: The recurring cost of keeping the property in working order — repairs, servicing and replacements.
Other ownership costs: Any remaining recurring cost of owning the property that the other fields do not cover.

The rent alternative

What you would pay per month to rent a comparable property, and how fast you assume that rent rises. This is the heart of the comparison: without it there is nothing to compare buying against.

Be careful that this is rent you would PAY, not rent you could charge. Rent you could charge is a different question, and it belongs in the Buy to Rent mode.

Comparable rent: What it would cost you per month to RENT a property like the one you are considering buying.
Rent growth: How much you assume rent rises each year, as a percentage.

Market assumptions

What the renter's invested money is assumed to earn each year, and how much of that is lost to fund and platform fees. Both are your assumptions, not recommendations, and together they set the price of the whole comparison: a high assumed return makes renting look strong, a low one makes buying look strong.

Enter the return before fees, and put the fees in the fee-drag field. Entering a return that already has fees taken out, and then also entering fee drag, subtracts them twice.

Investment return: The annual return you assume the renter earns on the money they did not spend on buying.
Investment fee drag: The yearly percentage lost to fund and platform fees, subtracted from the investment return.

Sale assumptions

What selling would cost: the agent's commission as a percentage of the eventual sale price, and any other one-time selling cost as an amount. These are applied whenever the buyer's position is measured, not only at the end, which is what makes the comparison against an investment account honest.

Selling commission: The agent's fee when you sell, as a percentage of the sale price.
Other sale costs: Any remaining one-time cost of selling that the commission does not cover.

Reading the Buy to Live results

The results are arranged in three levels: the verdict, the four figures the comparison turns on, and supporting detail underneath.

The verdict has three possible forms, and the third is as informative as the other two: when the two paths finish within a rounding tolerance of each other, the app says so rather than crowning a winner by an artifact.

Buy ahead

Under the assumptions you entered, the buying path ends the analysis period with more wealth than renting and investing.

How to read it: Both paths are measured the same way at the same moment: the buyer as if they sold and paid the selling costs, the renter as the value of their investments. This says the buying path finished higher.

What this does not mean

That you earn this amount. It is the gap between two projected end positions, not income.
That the money is available as cash. It is mostly tied up in a property you would have to sell to reach.
That buying is the right decision for you. The model knows nothing about your job security, your plans, or how long you will stay.
That this will happen. Change the appreciation or investment-return assumption and the verdict can reverse.

Rent + invest ahead

Under the assumptions you entered, renting and investing the difference ends the analysis period with more wealth than buying.

How to read it: The renter's investments finished higher than the buyer's position after selling costs. This result leans heavily on the investment return you assumed.

What this does not mean

That renting is generally better than buying. It is a result for this property, this horizon and these assumptions.
That the investment return will be achieved. It is a figure you entered, and real returns vary and can be negative.
That the comparison holds if you would not actually invest the difference. The whole renting path assumes that money is invested rather than spent.

Effectively tied

The two paths finish so close together that the difference is not meaningful.

How to read it: The app declines to name a winner rather than call one by a rounding artifact. In practice the numbers are not going to settle this for you, and the things the model does not capture matter more.

Beneath the verdict sit the four figures it is built from. The two headline tiles are the two sides of the comparison; the difference between them is the verdict's figure; and break-even answers the question the verdict cannot.

Buy liquidation net worth

What the buyer would be left with if they sold at that moment: the property's value, minus selling costs, minus the remaining mortgage.

How to read it: The buyer's side of the comparison, measured as if the property were actually sold at that moment — which is what makes it comparable with an investment account that could be cashed in at any time.

What this does not mean

The property's value. Selling costs and the outstanding loan have already been taken off.
Money in hand today. It is the position at the end of the analysis period, and only if a sale actually happened.

Rent + invest portfolio

The running value of the money the renter has invested instead of buying.

How to read it: The renter's side of the comparison: the up-front money the buyer would have spent, plus every monthly difference, grown at your investment return after fees.

Final difference

The gap between the two paths' end positions, in money.

How to read it: One end position subtracted from the other. The verdict above says which way it points.

What this does not mean

A profit or a gain. Neither path produces this amount; it is the distance between them.
A precise figure. It is the difference between two long projections, so a small change in either one moves it substantially.

Break-even

The point at which buying catches up with renting and investing, and stays ahead.

How to read it: Four outcomes are possible: ahead from the start, a confirmed point in time, a point too close to the end of the period to confirm, and not reached at all. Read it against how long you actually expect to stay.

What this does not mean

The point at which the mortgage is paid off, or at which the property has covered its own costs. It is purely the crossing point between the two paths.
A safe date to sell. It is a modelled crossing, not a plan, and it moves with every assumption.
That an unconfirmed result is an error. It means the crossing came too near the end of the period for the app to check that the lead held.
That 'not reached' means the calculation failed. It is a finding: within this horizon, buying did not overtake renting.

Break-even deserves a second look if you are unsure how long you will stay. Buying usually starts behind, because of everything paid up front, and break-even is the point at which it overtakes renting and stays ahead. If that point is later than you expect to hold the property, the final verdict may simply not apply to you. It has four possible outcomes: ahead from the start, a confirmed point in time, a crossing too near the end of the period to confirm, and not reached at all — the last two are findings, not errors.

The supporting detail below answers two further questions: what the property itself is worth at the end, and what cash each path consumed along the way.

Estimated property value

What the property is assumed to be worth at a given point, based on your appreciation assumption.

How to read it: The price you entered, carried forward at your appreciation assumption to the end of the analysis period. Treat it as the consequence of an assumption, not as a valuation of the property.

Remaining mortgage

How much of the loan is still owed at a given point.

How to read it: What is still owed on the loan at the end of the analysis period. It is zero for a cash purchase, and zero if the loan term ends before the horizon does.

Equity

The property's value minus what you still owe on it.

How to read it: The projected property value minus the remaining mortgage — a snapshot of position at the end of the period.

What this does not mean

Profit. It takes no account of the cash you put in, the years of payments you made, or what selling would cost.
Money you can spend. Reaching it means selling, which has costs, or borrowing against it, which creates a new debt.
A guaranteed amount. Most of the growth comes from an appreciation rate you chose.

Initial cash required

The money you need on day one: the down payment plus every one-time cost of buying.

How to read it: An affordability figure — whether you can do this at all — and a separate question from whether the purchase works out well over time.

Cumulative rent paid

The total rent the renting path pays out over the whole analysis period.

How to read it: Read it next to the buyer's cumulative cash requirement — on its own it makes renting look expensive without showing what buying costs.

Cumulative buyer cash requirement

The total cash the buying path has to pay out over the period — mortgage payments plus running costs.

How to read it: The fair thing to read cumulative rent paid against. Part of it — the principal — comes back through the eventual sale; the rest does not.

Buy to Live: Advanced Analysis

Once an analysis has run, three further tools appear below it. All three exist for the same reason: a single answer built on a forecast is fragile, and these show you how fragile.

Scenarios

The same property, analysed again under different assumptions. Three alternatives sit beside your own base case — a weaker market, a cautious case and a stronger market — and each changes only the assumptions you give it. Everything else is inherited from the analysis you already ran.

The names describe the direction of the change, not a probability. Nothing here says a weak market is unlikely, and the strong case is not a target. What matters is whether the scenarios agree: if they all point the same way, your conclusion is robust. If the verdict flips between them, the decision rests on a forecast nobody can make.

Scenario comparison

The same property analysed again under a different set of assumptions about the future.

How to read it: Your base case beside the alternatives you set up, each differing only in the assumptions you overrode. What matters is not which scenario wins but whether they agree: if the verdict flips between them, it rests on a forecast rather than on the property.

Sensitivity

Where scenarios move several assumptions at once, sensitivity moves exactly one and holds everything else still. You pick the assumption, and the app runs the analysis across a range of values for it, so you can see how much the answer actually depends on that one thing.

A steep curve means your conclusion is at the mercy of that assumption. A flat one means it barely matters and you can stop worrying about it. Because everything else is held fixed, the curve isolates one variable cleanly — which is its strength, and also its limit: real futures do not move one thing at a time, and the curve is not a forecast of what will happen.

Sensitivity

Changing one assumption across a range of values while holding everything else fixed, to see how much the answer moves.

How to read it: How the final difference responds as one assumption moves and everything else stays fixed. A steep curve means the conclusion depends heavily on that one assumption; a flat one means it barely matters.

Maximum purchase price

This turns the question around. Instead of asking whether a given price works, it searches for the highest price at which buying would still finish level with renting and investing, under the assumptions you already entered.

You choose what is held constant as the price moves: a fixed deposit percentage, so your cash grows with the price, or a fixed amount of cash, so the loan absorbs the whole increase. They answer different real questions and give different answers.

Maximum purchase price

The highest price at which buying still finishes level with renting and investing, under your assumptions.

How to read it: Solved while holding your chosen down-payment policy constant, and shown against the asking price so you can see the gap. Change the appreciation assumption or the horizon and the threshold moves.

What this does not mean

The property's market value. Nothing in this app looks at any market.
An appraisal or a professional valuation.
A fair price, or what the property is worth to anyone else.
A price you should offer. It is a threshold produced by your own assumptions, and it moves when they do.

Worked example: Buy to Live

Suppose you are deciding whether to buy a home or carry on renting something similar. This walkthrough runs that comparison from start to finish, explains what each number is for, and then — the part that matters most — shows how the answer changes when the assumptions do.

Everything below uses the calculator's own starting values, so you can open it in the other tab and follow along with exactly these figures. Every result shown is produced by the same engine the app runs; none of it is typed in by hand.

Two labels appear beside each input as we go. KNOWN means a figure you could look up for a real property — the price, the rate a lender quoted, what a similar home rents for today. ASSUMPTION means a guess about the future that nobody can look up. Keeping the two apart is most of the skill in using a tool like this.

Step 1 — The property

We start with what is being bought, and over how long we are going to judge it.

Purchase priceKnown: ฿8,000,000; The price agreed with the seller. In a real analysis this comes from the listing or the contract.
Analysis horizonAssumption: 10 years; How long the comparison runs. The property is treated as sold at the end of it.
Annual property appreciationAssumption: 3%; Nobody knows what property will do. This is the example's assumption, not a forecast and not a safe or recommended figure.

Notice which of those is an assumption. The price is a fact you could check. The appreciation rate is not: we do not know what the property will be worth in ten years, and neither does the calculator. It is the single most influential figure in the whole analysis, which is exactly why Step 10 goes back and tests it.

Step 2 — The financing

Next, how the purchase is paid for. A mortgage, with part of the price paid from your own money and the rest borrowed.

Purchase methodKnown: Mortgage
Down paymentKnown: 40%; The share of the price paid from your own money. Whatever is left is what you borrow.
Mortgage annual interest rateKnown: 5.25%; The yearly rate as a lender would quote it, held constant for the whole analysis.
Loan termKnown: 20 years; Longer than the analysis horizon here, so the loan is not finished when the property is sold.

You never type the loan amount: it follows from the price and the down payment. The price, minus what you pay yourself, is what the bank finances. The calculator shows both in money as you type, so the percentage never hides the real amount:

Cash down payment: ฿3,200,000
Loan amount: ฿4,800,000

The down payment is cash out of your pocket on day one. The loan is repaid monthly over the loan term, and those payments are part of what the buying path costs each month. Because the loan term here is longer than the analysis horizon, the mortgage is not finished when the property is treated as sold — whatever is still owed comes out of the sale.

Step 3 — The costs of buying and owning

Buying costs money beyond the price, once at the start and then continually for as long as you own the place. These are the example's figures for both.

Transfer / registration feesKnown: ฿0
Legal feesKnown: ฿0
RenovationKnown: ฿0
Furniture / appliancesKnown: ฿0
Mortgage setup costKnown: ฿0
Other initial costsKnown: ฿0

Common area / HOA fee (per month)Known: ฿0
Property tax (per year)Known: ฿0
Insurance (per year)Known: ฿0
Maintenance (per year)Known: ฿0
Other ownership costs (per month)Known: ฿0

It is worth being clear about which direction the omission runs. These are costs only the buying path would ever pay, so if the property you are analysing does have them, leaving them at zero makes the modelled buying path look stronger than it would with those costs included. Fill in the ones that apply to your property.

Step 4 — The rent alternative

Here is what makes this a comparison rather than a mortgage calculator. Buying is measured against a specific alternative, and that alternative needs its own assumptions.

Comparable rent (per month)Known: ฿30,000; What renting a similar home would cost today. Money you would PAY, not rent you could charge.
Annual rent growthAssumption: 3%; How fast that rent is assumed to rise. Another guess about the future.
Expected annual investment returnAssumption: 7%; What the renter's invested money is assumed to earn, before fees. One of the two assumptions that most often decides the answer.
Annual investment fee dragAssumption: 0%; Fund and platform fees subtracted from that return.

That distinction is the whole reason the comparison is worth anything. Measured against a renter who simply spends the difference, buying wins almost automatically, and the answer teaches you nothing. Measured against a renter who invests it, the two paths are genuinely competing — and the investment return you assume becomes as decisive as the appreciation rate.

Step 5 — The cost of selling

The last group is what it would cost to turn the property back into money.

Selling commissionKnown: 3%; Charged on the eventual sale price, so the amount grows if the property appreciates.
Other sale costsKnown: ฿0

It is reasonable to wonder why selling costs appear at all when you are not planning to sell. The reason is fairness. The renter's investments could be cashed in at any moment, so the buyer's position has to be measured the same way: as what would be left after actually selling and paying the costs of doing so. That figure is called the buy liquidation net worth, and it is what the comparison uses at every point in time — not the property's headline value.

Step 6 — The result

With all of that entered, the calculator projects both paths forward and compares where each one ends up.

Verdict

Buy ahead

Buying path, after selling costs: ฿7,414,157
Rent + invest path: ฿6,040,595
Difference, in favor of buying: ฿1,373,562

Under these assumptions the calculator returns "Buy ahead": after 10 years, the buying path finishes ฿1,373,562 further ahead than the other. That gap is the headline figure — and it is a gap, not money anyone receives.

Read the two figures above the difference and the arithmetic becomes obvious: one path's ending wealth, minus the other's. What is not obvious — and what the rest of this walkthrough is about — is how much either of those numbers depends on assumptions nobody can verify.

Step 7 — Break-even

The verdict answers "which path is ahead at the end?". Break-even answers a question that matters more if you are unsure how long you will stay: when does buying get ahead at all?

In this example break-even lands at 2 years: that is when the buying path overtakes renting and investing AND holds the lead for long enough that the app can confirm it.

Buying usually starts behind, because of everything paid up front, and the crossing point is where it catches up. The app deliberately does not report the first month buying briefly noses ahead — it reports the point from which the lead is sustained. There are four possible outcomes in total: ahead from the start, a confirmed point in time, a crossing too near the end of the period to confirm, and not reached within the horizon at all. This example shows only one of them; the other three are findings in their own right, not errors.

The practical use is simple. If break-even is later than you expect to hold the property, the final verdict is not really about you.

Step 8 — What you own at the end

Underneath the verdict, the calculator shows where the property itself stands at the end of the period.

Estimated property value: ฿10,751,331
Remaining mortgage: ฿3,014,634
Equity: ฿7,736,697

The arithmetic is just the projected value minus what is still owed. That remainder is your equity, and it has grown in two ways at once: the loan has been paid down every month, and the property has been assumed to gain value every year.

The other half of the picture is what each path actually cost along the way:

Initial cash required: ฿3,200,000
Cumulative rent paid: ฿4,126,997
Cumulative buyer cash requirement: ฿3,881,342

Those last two are the fair pair to read against each other. Total rent paid looks like money thrown away — until you notice that the buying path also spends money it never gets back, on interest, fees and upkeep, and that part of the buyer's cash requirement is principal that does come back through the sale.

Step 9 — Reading the charts

Three charts sit between the headline figures and the supporting detail. Each answers a different question, and once the numbers above make sense the lines are easy to read.

Net worth over time — the whole comparison in one picture. Two lines, one per path, and the point where they cross is break-even. What to look for: how early they cross, and how far apart they end. Two lines that stay close together mean the decision is finely balanced whatever the final verdict says.
Property value versus mortgage balance — the two forces behind equity. One line rises with the appreciation you assumed; the other falls as the loan is repaid. The gap between them at any moment is your equity, and watching it open up shows why equity grows slowly at first and faster later.
Annual cash requirement — what each path actually demands from you each year. This is the affordability chart rather than the wealth chart, and it is the one to look at if the question is not "which is better" but "can I sustain this".

None of the charts introduces new information: every line is drawn from the same projection the figures above came from.

Step 10 — Now challenge the answer

This is where a beginner stops and where a careful person keeps going. The result so far rests on assumptions nobody can verify — so the useful question is not "what is the answer?" but "how easily does the answer change?". The three advanced tools exist for exactly that.

First, scenarios: the same property, analysed again under weaker and stronger assumptions.

Bear
฿931,053
Rent + invest aheadChanges the answer
Conservative
฿174,735
Buy ahead
Bull
฿3,826,172
Buy ahead

In this example the Bear scenario reverses the answer entirely. Nothing about the property changed — only the assumptions did. That is the single most useful thing this tool can show you: whether your conclusion survives being wrong about the future.

Next, sensitivity: instead of moving several assumptions together, move exactly one and hold everything else still. Appreciation is the obvious candidate, because it is both the most influential figure and the least knowable. The tool sweeps a range of values; here are the two ends and the example's own value.

Property appreciation

1.00% appreciation
฿483,361
Rent + invest ahead
3.00% appreciationThis example
฿1,373,562
Buy ahead
5.00% appreciation
฿3,584,994
Buy ahead

The tool sweeps 9 values across the range; three of them are shown here.

The verdict is not the same at both ends of the range: at 1.00% appreciation the answer is "Rent + invest ahead", and at 5.00% it is "Buy ahead". Somewhere between those two guesses the conclusion changes — which means this single assumption, not the property, is what the answer turns on.

Finally, maximum purchase price turns the question around: rather than asking whether this price works, it searches for the highest price that would still finish level with renting and investing.

Maximum purchase price

฿10,489,852

฿2,489,852 above the example's asking price

Under this example's assumptions the solver reports ฿10,489,852 — ฿2,489,852 above the example's asking price. It is a threshold produced by the assumptions above, and nothing else.

Step 11 — What the example taught

The calculator compares two strategies, not two prices.
Some inputs are facts you can look up; appreciation, rent growth and investment returns are not.
Buying carries one-time costs, ongoing costs and selling costs; leaving out the ones a property actually has makes the modelled buying path look stronger than it would with them included.
Renting is measured against investing the difference, which is what makes the comparison meaningful.
The headline difference is a modelled gap between two paths, not profit and not cash.
Equity is not profit either: it ignores what you put in and what selling costs.
Break-even depends on the same assumptions as everything else, and matters most if you might move.
Changing one assumption can reverse the conclusion entirely.
The advanced tools exist to find that out on purpose, rather than by accident.
The output is information for a decision you make — never the decision itself.

Try it yourself

The best way to make this stick is to reproduce it. Open the calculator, run it once as it comes, and check that you get the figures above. Then start changing things one at a time and watch what moves: drop the appreciation rate, raise the investment return, put a realistic maintenance figure in, shorten the horizon to three years. You will learn more from five minutes of that than from re-reading this page.

Open the calculator

Buy to Rent: the question it answers

"If I buy this property and let it to a tenant, what does it actually produce — and what would I be left with when I sell?"

That breaks into two separate questions, and the results answer them separately. The first is about the year ahead: does the rent cover the costs of running the property and the mortgage payments, and how does the income compare with what the property cost? The second is about the whole period: how much cash accumulated, how much of the loan was paid off, what the property was worth, what a sale would leave, and what all of that amounts to as a return on the money you put in.

There is no rent-versus-buy comparison in this mode, and no fictional renter investing anything. It is an appraisal of one property as an income investment.

Buy to Rent: filling in the form

Property, financing, acquisition costs, ownership costs and sale assumptions all work exactly as they do in Buy to Live — the sections above apply unchanged. What is different is the rental income group.

Enter the full monthly rent a tenant would pay, as if the property were let for the whole year. Empty periods are handled separately by the occupancy field, so reducing the rent yourself to allow for vacancy would count the same loss twice. Occupancy is entered as occupancy, not as vacancy: a property empty for about two and a half weeks a year is 95% occupied, not 5%.

The management fee is what a letting agent charges. It is applied to the rent actually collected rather than to the rent that was scheduled but never received, which is how agents are normally paid. Enter zero if you will manage the property yourself — remembering that self-managing is free of cash, not free of your time.

Expected monthly rent: What a tenant pays you per month when the property is let, before allowing for empty periods.
Occupancy: The share of the year the property is actually let and paying rent, as a percentage.
Vacancy loss: The rent not collected because the property was empty for part of the year.
Property management fee: The share of rent paid to an agent for managing the property and its tenants, as a percentage.
Rent growth: How much you assume rent rises each year, as a percentage.

Reading the Buy to Rent results

The headline states the first year's cash position in plain terms — whether the rent covers the running costs and the mortgage, with a surplus, a shortfall, or almost exactly. It is a statement about cash, never a verdict on the investment.

Positive cash flow

In the first year, the rent covers the running costs and the mortgage payments, with money left over.

How to read it: The figure shown is that surplus, for year one only and before income tax. Later years differ as the rent, the costs and the loan all change.

What this does not mean

That the investment is profitable overall. Profit also depends on what the property is worth when you sell and what selling costs.
That it is a good investment. A small surplus on a large amount of your own cash can still be a poor return.
That the return is adequate. Compare it against the cash you invested, using cash-on-cash return.
That later years look the same. Rent, costs and the loan all change over time.

Negative cash flow

In the first year, the rent does not cover the running costs and mortgage payments — the shortfall has to come from elsewhere.

How to read it: This much has to come from elsewhere every year. It is a fact about cash, not a verdict on the investment — but it is money you must actually have available.

Break-even cash flow

In the first year, the rent covers the running costs and mortgage payments almost exactly.

How to read it: Nothing spare, and nothing to find. Later years will differ, as the rent, the costs and the loan all change.

Below the headline sit the year-one measures. They divide neatly in two: some describe the PROPERTY, and are the same for any buyer however they financed it; others describe YOUR DEAL, and change entirely with how much you borrowed.

About the property: gross rental yield, net operating income and cap rate. The mortgage is deliberately left out of all three, which is exactly what lets you compare one property with another.
About your deal: cash-on-cash return, DSCR and the cash you invested. These count the mortgage, because it comes out of your pocket.

Gross rental yield

A year's full rent as a percentage of the purchase price, before any costs at all.

How to read it: Useful for a first sort across listings, and always higher than what you would actually earn once the costs of running the property are taken out.

Net operating income

The money the property itself produces in a year: rent collected, minus the costs of running it, and before any mortgage payment.

How to read it: The same figure for any buyer of this property, however they financed it — which is what makes it comparable across properties. Your own mortgage appears further down.

What this does not mean

Cash flow. The mortgage payment has not been deducted yet — cash flow is the line further down.
Profit. It ignores financing entirely, and takes no account of what you paid for the property or what selling it costs.
That the mortgage was left out by mistake. It is excluded on purpose, so the property can be compared with properties financed differently.

Cap rate

The property's yearly operating income as a percentage of its purchase price, before any mortgage payments.

How to read it: Use it to compare this property against others: because financing is excluded, the comparison is like for like whatever each buyer borrowed.

What this does not mean

The return on your own cash. It measures against the full purchase price, not the amount you actually put in.
Something that improves with better financing. Borrowing terms do not appear in it at all — that is the point of the measure.
A yield you receive. It describes the property's income, not money paid to you after the mortgage.

Cash-on-cash return

One year's cash flow as a percentage of the cash you actually put in.

How to read it: Compare it with the cap rate to see what borrowing did to your return. Shown as not applicable when no cash was invested, because there would be nothing to measure against.

What this does not mean

The same thing as cap rate. Cap rate is the property's income against its price; this is your cash flow against your money, after the mortgage.
Your total return. It ignores the loan being paid down and any change in the property's value.
A rate you keep. It is one year's figure, before tax, and later years differ.

DSCR

How many times over the property's operating income covers a year of mortgage payments.

How to read it: Each lender sets its own requirement, so read it as a cushion rather than as a pass mark. Shown as not applicable for a cash purchase, because there is no debt to cover.

What this does not mean

That any particular value passes or fails. Lenders set their own requirements, and this app does not define a threshold.
That a figure above 1.0 means the property pays you. It means operating income covers the loan payments; your own cash flow is a separate line.
That it is fixed. It changes as rent, costs and the loan change over the years.

Initial cash invested

The total of your own money that goes in at purchase: the down payment plus every one-time cost.

How to read it: This is what every return on this page is measured against, which is why two buyers of the same property can see very different returns.

Further down, the results move from one year to the whole holding period: what the property is worth at the end, how much of the loan remains, and the three figures that summarise the outcome.

Estimated property value

What the property is assumed to be worth at a given point, based on your appreciation assumption.

How to read it: The price you entered, carried forward at your appreciation assumption to the end of the analysis period. Treat it as the consequence of an assumption, not as a valuation of the property.

Remaining mortgage

How much of the loan is still owed at a given point.

How to read it: What is still owed on the loan at the end of the analysis period. It is zero for a cash purchase, and zero if the loan term ends before the horizon does.

Equity

The property's value minus what you still owe on it.

How to read it: The projected property value minus the remaining mortgage — a snapshot of position at the end of the period.

What this does not mean

Profit. It takes no account of the cash you put in, the years of payments you made, or what selling would cost.
Money you can spend. Reaching it means selling, which has costs, or borrowing against it, which creates a new debt.
A guaranteed amount. Most of the growth comes from an appreciation rate you chose.

Cumulative pre-tax cash flow

Every year's cash flow added together over the whole holding period.

How to read it: Negative years are included at their real value, so early losses genuinely offset later gains. The figures are summed at face value — nothing is assumed to have been reinvested.

Net sale proceeds

The cash left over from selling: the sale price, minus selling costs, minus whatever is still owed on the mortgage.

How to read it: The cash left from selling at the end of the holding period, after the selling commission, other sale costs and repaying the remaining loan. It is before any tax on the gain.

Total investment profit

Everything you got out, minus everything you put in: the cash flow collected plus the net sale proceeds, less the cash you invested.

How to read it: The nearest thing to a bottom line for the whole holding period. Read it beside the return figures: a large profit, on a large amount of cash, over many years can still be a weak return.

What this does not mean

Cumulative cash flow. That is only the money collected along the way; this also includes what the sale produced and subtracts what you invested.
Equity. Equity ignores your invested cash and the costs of selling.
Net sale proceeds. Those are one component of it.
A return. A large profit on a very large amount of cash over many years may still be a weak return — that is what the return figures are for.

Simple return on invested cash

Total profit as a percentage of the cash you invested, over the whole holding period — not per year.

How to read it: One figure covering the entire holding period, so it does not compare a three-year hold with a fifteen-year one. The annualized return exists for exactly that.

What this does not mean

A yearly return. It is NOT annualized: 166% over ten years is not 166% a year.
Something comparable across different holding periods. It almost always rises the longer you hold, simply because there is more time to accumulate.
An IRR or a CAGR. Neither is implemented here.

The operating statement, line by line

This is the panel that makes the whole rental analysis legible. It is a household budget for the property's first year: start with the rent it could earn, take off the rent you will not collect, take off what it costs to run, and take off the mortgage. What is left is yours.

Gross scheduled rent
A full year at the monthly rent you entered, as if the property were never empty.
minusVacancy loss
The rent you do not collect because the property stands empty part of the year. Not a bill you pay — income that never arrives. It follows directly from the occupancy figure, and it is the only place empty periods are accounted for anywhere in the analysis.
equalsEffective rental income
The rent actually collected. The management fee is charged on this figure rather than on the line above it.
minusOperating expenses
The cost of running the property for the year — management, maintenance, insurance, property tax, the service charge and anything else you entered. The mortgage is deliberately not among them.
equalsNet operating income
What the property itself produces. Because financing is excluded, this figure is the same for any buyer of this property, whatever they borrowed — which is what makes it comparable across properties, and what makes it the basis of the cap rate.
minusDebt service
A year of mortgage payments, interest and principal together. It sits here, below net operating income and never inside it, because it depends on how you financed the purchase rather than on the property.
equalsPre-tax cash flow
What the year leaves in your pocket, before any income tax. This can be negative, which means the property costs you money that year.

Reading it downwards shows why two of the figures are so often confused. Net operating income and pre-tax cash flow are separated by exactly one line — the mortgage — and that single line is the difference between describing a property and describing your deal.

Exit strategy: when you sell

The main analysis assumes you sell at the end of the horizon you entered. Exit strategy asks what would happen if you sold at other times instead. It re-runs the same analysis at several holding periods — three, five, seven, ten and fifteen years — changing nothing but the holding period. Each row is a complete analysis in its own right.

The reason this tool exists is a trap in the numbers. Total profit and simple return almost always rise the longer you hold, simply because there has been more time to accumulate — so judged on those alone, holding forever always wins. The annualized return does not have that bias: it restates each result as a steady per-year rate, so a three-year hold and a fifteen-year hold can be compared fairly. That is why it is the only figure the tool charts.

Annualized return

The steady yearly rate that would have turned your invested cash into what you end up with, over the holding period.

How to read it: The whole-period result restated as a steady yearly rate, so holding periods of different lengths can be compared fairly. Shown as not applicable where there is no cash invested to measure against, or where the outcome does not repay it.

What this does not mean

An IRR. IRR accounts for the timing of every individual cash flow; this compares one starting amount with one ending amount.
A money-weighted return. Neither that nor IRR is implemented in this app.
A rate that assumes your rental income was reinvested. Interim cash flow is counted at face value and assumed to earn nothing afterwards.
A return you will receive each year. Actual yearly results vary widely; this is an average rate that produces the same end point.

Two markers appear in the table. Neither is advice.

Highest

A marker showing which of the holding periods you selected produced the highest annual rate — under your assumptions, and among those periods only.

How to read it: Marks one row of the table you asked for. Change the periods you selected, or any assumption, and the marker can move to a different row.

What this does not mean

The optimal time to sell. It is the best row in a table you chose, not an optimum found across all possible dates.
A recommendation to sell then. The app never recommends an action.
A guarantee about the future. Change the appreciation or rent-growth assumption and the marker can move to another row.
That the other periods are bad. A slightly lower annual rate over a longer hold can still suit you better.

Current

A marker showing which row matches the analysis horizon you entered on the form.

How to read it: An orientation aid only, so you can see where your own assumption sits among the alternatives. It carries no judgement about that period.

Worked example: Buy to Rent

Suppose you are considering buying a property to let, rather than to live in. This walkthrough follows the rent all the way through: what the tenant pays, what never arrives, what the property costs to run, what the mortgage takes, what is left, and what the whole thing amounts to when you eventually sell.

As with the Buy to Live example, it uses the calculator's own starting values and every figure is produced by the same engine the app runs. Open the calculator in the other tab and you can follow along with exactly these numbers.

Step 1 — The property and the financing

The property side is identical to a home purchase: what it costs, how long it is held, and what its value is assumed to do.

Purchase priceKnown: ฿8,000,000; What the property costs to buy. Every yield on this page is measured against it.
Analysis horizonAssumption: 10 years; How long the property is held before it is treated as sold.
Annual property appreciationAssumption: 3%; A guess about the future, not a forecast. It decides what the sale is worth at the end.

The financing decides two things that matter later — how much cash is tied up, and how big the monthly payments are.

Purchase methodKnown: Mortgage
Down paymentKnown: 40%; The share paid from your own money. It sets both the loan and the cash your returns are measured against.
Mortgage annual interest rateKnown: 5.25%
Loan termKnown: 20 years

Cash down payment: ฿3,200,000
Loan amount: ฿4,800,000

Keep both figures in mind. The cash down payment is what the returns further down are measured against, and it drives cash-on-cash return. The loan drives the debt service, which decides the cash flow and the DSCR, and what remains of it comes out of the sale at the end.

Step 2 — The rent

Now the part that makes this a rental analysis. Four assumptions describe what the property earns.

Expected rental income (per month)Observed: ฿40,000; The full monthly rent as if the property were let all year. What comparable properties nearby actually achieve.
OccupancyObserved: 95%; The share of the year the property is let and paying. This is the only place empty periods are accounted for.
Annual rent growthAssumption: 2%; How fast the rent is assumed to rise each year.
Property management feeKnown: 0%; Charged on the rent actually collected. Zero here means the example assumes self-management, which costs time rather than cash.

Step 3 — Following the rent down the statement

This is the panel that makes the whole analysis legible. Read it downwards: each line takes something off the one above, and the last line is what actually reaches you.

Gross scheduled rent
฿480,000
A full year at the monthly rent above, as if the property were never empty.
minusVacancy loss
฿24,000
The rent not collected because the property stands empty part of the year. Income that never arrives, not a bill you pay.
equalsEffective rental income
฿456,000
The rent actually collected. A managing agent's fee would be charged on this figure, not on the line above it.
minusOperating expenses
฿0
A year of running costs — management, maintenance, insurance, tax and the service charge. The mortgage is deliberately not among them.
equalsNet operating income
฿456,000
What the property itself produces. The same figure for any buyer of this property, whatever they borrowed.
minusDebt service
฿388,134
A year of mortgage payments, interest and principal together. It sits here because it depends on the financing, not on the property.
equalsPre-tax cash flow
฿67,866
What the year leaves in your pocket, before any income tax.

Two of those lines read as zero in this example, and that is worth stopping on. The operating expenses are zero because every cost field is zero in the calculator's starting values:

Transfer / registration feesKnown: ฿0
Legal feesKnown: ฿0
RenovationKnown: ฿0
Furniture / appliancesKnown: ฿0
Mortgage setup costKnown: ฿0
Other initial costsKnown: ฿0

Common area / HOA fee (per month)Known: ฿0
Property tax (per year)Known: ฿0
Insurance (per year)Known: ฿0
Maintenance (per year)Known: ฿0
Other ownership costs (per month)Known: ฿0

One cost has no field at all: the agent's fee and marketing cost of finding a new tenant between lets. The calculation engine has a separate place for those, but the current simple form does not expose an input for them, so they are not in this statement. Where turnover matters, fold your estimate into the maintenance or other-ownership figure.

Step 4 — The year-1 cash position

The last line of the statement is what the app puts at the top of the results, monthly and yearly.

Year 1 cash flow

Positive cash flow

฿5,655/ month

฿67,866 / year

In year 1 the rent covers operating costs and debt service, with this much left over.

In this example year 1 leaves a surplus: the rent collected covers the running costs and the mortgage, with something left over.

Step 5 — Gross yield and cap rate

Two measures describe the PROPERTY rather than your deal. Both ignore the mortgage entirely, which is exactly what makes them comparable from one property to another.

Gross rental yield: 6.00%; A full year of scheduled rent against the purchase price, before every cost.
Net operating income: ฿456,000; Year 1 rent collected, less the cost of running the property, before any mortgage payment.
Cap rate: 5.70%; That operating income against the purchase price. Financing is excluded, which is what makes it comparable across properties.

The gross rental yield is 6.00% and the cap rate is 5.70%. They differ because they start from different lines of the statement above: the gross yield uses the full scheduled rent, while the cap rate uses net operating income — rent actually collected, after the cost of running the property. Neither one accounts for the mortgage, and neither is a judgement about whether the property is worth buying.

Neither figure is a verdict. There is no threshold in this app above which a cap rate becomes good, because no such universal threshold exists — what counts as reasonable depends on the country, the type of property, the alternatives available to you and the risk you are taking. They are descriptions, and their use is comparison.

Step 6 — Cash-on-cash return

Now the same year, measured against your own money instead of against the price.

Initial cash invested: ฿3,200,000; Down payment plus every one-time cash cost at purchase. This is what the returns below are measured against.
Cash-on-cash return: 2.12%; Year 1 cash flow as a percentage of that invested cash — after the mortgage, unlike the cap rate.
DSCR: 1.17; How many times over the property's operating income covers a year of mortgage payments.

Cash-on-cash return comes out at 2.12%, against a cap rate of 5.70%. They are not competing versions of the same number: the cap rate describes the property against its full price and ignores borrowing, while cash-on-cash describes this deal — a year's cash flow, after the mortgage, against the cash actually put in.

Because it counts the mortgage, borrowing moves it in either direction: more leverage raises it when the rent comfortably covers the payments and sinks it when it does not. It is also only one year, and only cash — it ignores the loan being paid down and any change in the property's value, so it is not the investment's total return.

Step 7 — Debt service coverage

DSCR comes out at 1.17. A value of 1.00 would mean the property's operating income exactly covers the year's mortgage payments; above that there is a cushion, and below it part of the payments has to be met from money the property did not produce. Lenders set their own requirements and this calculator models no lender's underwriting rules, so read it as a cushion, not as a pass mark.

It is a lender's question more than an investor's: can the property's own income meet the loan payments? The calculator reports the ratio and stops there. It does not know which lender you are talking to, what that lender requires, or whether any particular property would be approved — those rules vary by lender, country and loan type, and none of them is modelled here.

Step 8 — What you own at the end

Jump to the end of the holding period. The property has been assumed to gain value each year, and the loan has been paid down every month.

Estimated property value: ฿10,751,331
Remaining mortgage: ฿3,014,634
Property equity: ฿7,736,697

The last line is simply the first minus the second — what the property is projected to be worth, less what is still owed on it.

Step 9 — Reading the two charts

The Buy to Rent results carry two charts, and both extend the single year you have just read through time.

Annual cash flow — one bar per year of the holding period. They are not all the same height: the rent is assumed to grow each year while the mortgage payment stays fixed, so a property can start negative and turn positive, or simply widen its surplus. What to look for is the shape, and whether any year demands money from you rather than paying you.
Property value versus mortgage balance — one line rising with the appreciation you assumed, the other falling as the loan is repaid. The gap between them at any moment is your equity, which is why it widens from both directions at once. The rising line is an assumption, not a measurement; the falling one is arithmetic on the loan.

Neither chart introduces anything new. Every point is drawn from the same year-by-year projection the figures above came from.

Step 10 — Selling at the end

The analysis assumes the property is sold at the end of the holding period. Selling is not free, and the loan has to be cleared out of the proceeds.

Projected sale price: ฿10,751,331
Total selling costs: ฿322,540; The commission and any other sale costs, charged on the sale price.
Remaining mortgage repaid: ฿3,014,634
Net sale proceeds: ฿7,414,157; What is actually left from the sale. Before any tax on the gain.

Net sale proceeds are not the property's value, not the equity, and not the investment's profit. They are what is actually left in hand from the sale after its costs and the outstanding loan — and before any tax on the gain, which this app does not model.

Step 11 — Total investment profit

Now the pieces come together. The cash collected along the way, plus what the sale left, less what you put in at the start.

Over 10 years those yearly figures add up to +฿1,111,730. That is money collected along the way — not the investment's profit, which still has the sale and the cash you invested to account for.

Cumulative pre-tax cash flow: +฿1,111,730; Every year's cash flow over the holding period, added together at face value.
Net sale proceeds: ฿7,414,157
Initial cash invested: ฿3,200,000
Total investment profit: +฿5,325,888; Everything the investment returned, less everything put into it. Pre-tax.
Simple return on invested cash: +166.43%; That profit as a percentage of the invested cash, across the whole holding period.

Step 12 — Simple return, and what it is not

The simple return here is +166.43%. That is the return across the WHOLE 10 years, not a yearly rate — it is not annualized, and reading it as an annual figure would overstate the result many times over.

Step 13 — Exit strategy and the annualized return

The exit strategy tool re-runs the whole analysis at several holding periods, changing nothing but how long the property is held. Each row is a complete analysis in its own right.

3 years
Annualized return
10.79%
Simple return
36.00%
Total profit
+฿1,151,980
5 yearsHighest
Annualized return
11.05%
Simple return
68.90%
Total profit
+฿2,204,776
7 years
Annualized return
10.81%
Simple return
105.17%
Total profit
+฿3,365,532
10 yearsCurrent
Annualized return
10.30%
Simple return
166.43%
Total profit
+฿5,325,888
15 years
Annualized return
9.48%
Simple return
289.06%
Total profit
+฿9,250,012

The annualized return is the column that makes those rows comparable. It restates each whole-period outcome as a steady per-year rate, by comparing one amount at the start — the cash you invested — with one amount at the end: the cash flow collected plus the net sale proceeds. Interim rental income is counted at face value and assumed to earn nothing afterwards. That is deliberately NOT an internal rate of return and NOT a money-weighted return; neither is implemented in this app, and the two answer a different question.

Look at the two return columns together and something counterintuitive appears. The simple return keeps climbing all the way out to 15 years, because there is simply more time to accumulate — but the annualized return peaks at 5 years and falls away after it. More total return over more years does not mean a higher rate of return per year, and that is exactly why the tool charts the annualized figure rather than the simple one.

The 10 years row is marked Current because it matches the horizon this analysis used, and its annualized return is 10.30%. The 5 years row is marked Highest, meaning it produced the largest annualized return among these preset periods under these assumptions — not that anyone should sell then.

Step 14 — What the example taught

Gross rent is not take-home income; it is the first line of a statement, not the last.
Occupancy is where uncollected rent is accounted for, and nowhere else.
Net operating income comes before the mortgage; cash flow comes after it.
Positive cash flow means the year paid for itself, not that the investment is a good one.
Cap rate describes the property; cash-on-cash describes your deal, and financing moves only the second.
DSCR measures whether the property's income covers the loan payments — not investment quality, and not any lender's approval.
Equity is not profit, and net sale proceeds are not profit either.
Total investment profit is the figure that nets everything against the cash you actually invested.
Simple return covers the whole holding period and is not a yearly rate.
Annualized return is a terminal-wealth measure that assumes no reinvestment — it is not an IRR.
The highest annualized return among the preset periods is not advice about when to sell.
Every one of these figures follows from assumptions you chose, and changes when they do.

Try it yourself

Open the calculator, switch to Buy to Rent, and run it as it comes — you should get exactly the figures above. Then start changing one thing at a time. Put a realistic service charge and maintenance figure in and watch the cap rate and the cash flow move together. Drop occupancy and see how quickly a surplus disappears. Add a management fee. Each change teaches more than another paragraph here could.

Open the calculator

Common beginner mistakes

These come up often. None of them is foolish — most are the natural reading of a number that happens to mean something slightly different.

Entering an appreciation rate that is really a hope. It is the most influential figure in the analysis and the least knowable. Test a range instead of committing to one.
Treating the investment return as guaranteed. It is an assumption you typed, and real returns vary and can be negative. The whole Rent + Invest side rests on it.
Forgetting the one-time costs of buying. Transfer fees, legal fees and renovation are real cash on day one, they lower every return measured against your money, and they are money you would not spend if you rented.
Leaving ownership costs at zero. The fields start at zero so nothing is assumed for you — not because a property costs nothing to keep.
Mixing up the billing periods. The service charge and other recurring costs are monthly; property tax, insurance and maintenance are yearly. A yearly figure in a monthly field is twelve times too big.
Confusing the down payment with the loan. The down payment is what you pay; the loan is the rest of the price. The form shows both in money as you type.
Comparing gross rent with cash flow. Rent is the top line of the statement; cash flow is what survives vacancy, running costs and the mortgage.
Reading net operating income as cash flow. They are one line apart, and that line is the mortgage.
Reading equity as profit. Equity ignores everything you put in and everything selling would cost.
Assuming positive cash flow means a good investment. A small surplus on a large amount of your own cash can still be a weak return, and cash flow says nothing about what the property is worth when you sell.
Reading "Buy ahead" as advice to buy. It says one modelled path finished higher than another under your assumptions. It knows nothing about your job, your plans, or how long you will stay.
Treating the maximum purchase price as what the property is worth. It is a threshold produced by your own assumptions, not a valuation.
Treating the highest annualized return as advice on when to sell. It describes a table you asked for.
Forgetting occupancy. Rent collected is not rent scheduled, and the occupancy field is the only place that difference is accounted for.
Choosing assumptions that produce the answer you already wanted. It is easy to do without noticing — and the scenario and sensitivity tools exist precisely to catch it.

What this calculator does not include

Knowing what a model leaves out is part of using it honestly. Some of these are deliberate omissions from the financial model; others are things the underlying engine can represent but the current simple form does not yet ask for. They are separated below, because the difference matters.

Not modelled at all:

Personal income tax on rental income.
Depreciation, capital allowances or any other tax relief.
Capital gains tax, or any other tax on the sale.
Internal rate of return (IRR) and money-weighted returns. The annualized return offered here is a different, simpler measure, and is not a substitute for either.
Probability, simulation or Monte Carlo analysis. Uncertainty is explored by testing assumptions yourself, through the scenario and sensitivity tools.
Currency conversion. One analysis uses one currency throughout.
Refinancing, changing interest rates, or a mortgage whose rate is not fixed for its whole term.

Supported by the calculation engine, but not asked for in the current simple form:

Tenant-turnover and leasing costs — the agent's fee and marketing cost of finding a new tenant. The engine has a separate, non-overlapping place for these, distinct from the occupancy figure, but the current form does not expose a field for them. Where they matter, the practical workaround is to include them in your maintenance or other ownership costs estimate.
Maintenance as a percentage of the property's value, rather than as a fixed yearly amount.
Cost items expressed as a percentage of the price rather than as an amount.

Not yet in the product:

Saving, naming or reloading an analysis. Everything lives in the page while you work, and leaving or reloading it starts fresh.
Exporting results to a file or a spreadsheet.
Custom holding periods in the exit strategy tool — the five preset periods are fixed for now.

Glossary

Every term the calculator uses, in plain English. These are the same definitions the ? beside each field and each result shows, so nothing here contradicts what you see while you work.

Property and time

Purchase price: The agreed price of the property itself, before any of the extra one-time costs of buying it.
Currency: The currency every amount in this analysis is entered and displayed in.
Property appreciation: How much you assume the property's value changes each year, as a percentage.
Property value: What the property is assumed to be worth at a given point, based on your appreciation assumption.
Analysis horizon: How many years the analysis runs for. Every result is measured at the end of this period.
Holding period: How many years you hold the property before selling it.

Financing

Purchase method: Whether you are paying for the property with a mortgage or entirely with your own cash.
Cash purchase: Buying without a loan — you pay the full price yourself.
Mortgage: A loan secured against the property, repaid in equal monthly payments over an agreed number of years.
Down payment: The part of the purchase price you pay from your own money, rather than borrowing.
Loan amount: How much you borrow: the purchase price minus your down payment.
Mortgage interest rate: The annual interest rate on the loan, as your lender quotes it.
Loan term: How many years the mortgage is scheduled to be repaid over.
Debt service: The total mortgage payments made in a year — the interest, plus the part of each payment that repays what you borrowed.
Remaining mortgage balance: How much of the loan is still owed at a given point.

Purchase and ownership costs

Transfer and registration fees: One-time official costs of legally transferring the property into your name.
Legal fees: One-time cost of the lawyer or conveyancer handling the purchase.
Renovation costs: One-time money spent on the property after buying it, before it is ready to live in or let.
Furniture and appliances: One-time cost of furnishing and equipping the property.
Mortgage setup costs: One-time fees charged for arranging the loan, such as arrangement or origination fees.
Other initial costs: Any remaining one-time cost of buying that the other fields do not already cover.
Total acquisition costs: All the one-time costs of buying, added together, on top of the purchase price.
HOA / common area fee: The recurring charge paid to the building or estate for shared maintenance and services.
Property tax: The recurring tax charged on owning the property.
Insurance: The recurring cost of insuring the property.
Maintenance: The recurring cost of keeping the property in working order — repairs, servicing and replacements.
Other ownership costs: Any remaining recurring cost of owning the property that the other fields do not cover.
Total ownership costs: All the recurring costs of owning the property for a year, added together.

Buy to Live

Comparable rent: What it would cost you per month to RENT a property like the one you are considering buying.
Rent growth: How much you assume rent rises each year, as a percentage.
Investment return: The annual return you assume the renter earns on the money they did not spend on buying.
Investment fee drag: The yearly percentage lost to fund and platform fees, subtracted from the investment return.
Rent + invest strategy: The alternative buying is compared against: rent a similar property, and invest the money you would otherwise have put into buying.
Renter investment portfolio: The running value of the money the renter has invested instead of buying.
Buy ahead: Under the assumptions you entered, the buying path ends the analysis period with more wealth than renting and investing.
Rent + invest ahead: Under the assumptions you entered, renting and investing the difference ends the analysis period with more wealth than buying.
Effectively tied: The two paths finish so close together that the difference is not meaningful.
Final difference: The gap between the two paths' end positions, in money.
Buy liquidation net worth: What the buyer would be left with if they sold at that moment: the property's value, minus selling costs, minus the remaining mortgage.
Break-even: The point at which buying catches up with renting and investing, and stays ahead.
Break-even: from the start: Buying was ahead from the very beginning — there was never a gap to catch up.
Break-even: unconfirmed: Buying moves ahead close to the end of the analysis period, with too little time left to confirm the lead holds.
Break-even: not reached: Buying never catches up within the analysis period you chose.
Initial cash required: The money you need on day one: the down payment plus every one-time cost of buying.
Cumulative rent paid: The total rent the renting path pays out over the whole analysis period.
Cumulative buyer cash requirement: The total cash the buying path has to pay out over the period — mortgage payments plus running costs.

Rental investing

Expected monthly rent: What a tenant pays you per month when the property is let, before allowing for empty periods.
Occupancy: The share of the year the property is actually let and paying rent, as a percentage.
Vacancy loss: The rent not collected because the property was empty for part of the year.
Property management fee: The share of rent paid to an agent for managing the property and its tenants, as a percentage.
Gross scheduled rent: The full year's rent the property would earn if it were let for the entire year.
Effective rental income: The rent you actually collect in a year, after allowing for empty periods.
Operating expenses: The yearly costs of running the property — management, maintenance, insurance, tax, HOA and similar.
Net operating income (NOI): The money the property itself produces in a year: rent collected, minus the costs of running it, and before any mortgage payment.
Pre-tax cash flow: What is left in your pocket for the year after running costs and mortgage payments — before any income tax.
Positive cash flow: In the first year, the rent covers the running costs and the mortgage payments, with money left over.
Negative cash flow: In the first year, the rent does not cover the running costs and mortgage payments — the shortfall has to come from elsewhere.
Break-even cash flow: In the first year, the rent covers the running costs and mortgage payments almost exactly.
Gross rental yield: A year's full rent as a percentage of the purchase price, before any costs at all.
Cap rate: The property's yearly operating income as a percentage of its purchase price, before any mortgage payments.
Cash-on-cash return: One year's cash flow as a percentage of the cash you actually put in.
DSCR (debt service coverage ratio): How many times over the property's operating income covers a year of mortgage payments.

Sale and exit

Equity: The property's value minus what you still owe on it.
Selling commission: The agent's fee when you sell, as a percentage of the sale price.
Other sale costs: Any remaining one-time cost of selling that the commission does not cover.
Net sale proceeds: The cash left over from selling: the sale price, minus selling costs, minus whatever is still owed on the mortgage.
Exit strategy: The same rental purchase compared across several possible holding periods, to see how the outcome changes with when you sell.

Returns

Initial cash invested: The total of your own money that goes in at purchase: the down payment plus every one-time cost.
Cumulative pre-tax cash flow: Every year's cash flow added together over the whole holding period.
Total investment profit: Everything you got out, minus everything you put in: the cash flow collected plus the net sale proceeds, less the cash you invested.
Simple return on invested cash: Total profit as a percentage of the cash you invested, over the whole holding period — not per year.
Annualized return: The steady yearly rate that would have turned your invested cash into what you end up with, over the holding period.
Terminal wealth: What you finish with in total: all the cash flow collected over the period, plus the net proceeds of selling.
Highest annualized return among selected periods: A marker showing which of the holding periods you selected produced the highest annual rate — under your assumptions, and among those periods only.
Current holding period: A marker showing which row matches the analysis horizon you entered on the form.
Everything here is before tax: No income tax, capital gains tax or tax relief is modelled anywhere in this app.

Advanced analysis

Scenario: The same property analysed again under a different set of assumptions about the future.
Base case: Your own assumptions, exactly as entered — the case every scenario is compared against.
Bear, Conservative and Bull scenarios: Three ready-made variations — a weak market, a cautious case, and a strong market — each starting from your own assumptions.
Sensitivity analysis: Changing one assumption across a range of values while holding everything else fixed, to see how much the answer moves.
Sensitivity variable: The single assumption a sensitivity run varies, while every other assumption stays exactly as you entered it.
Maximum purchase price: The highest price at which buying still finishes level with renting and investing, under your assumptions.
Down-payment policy: What is held constant while the app tries different purchase prices: the down payment percentage, or a fixed amount of cash.