Rent vs Buy Calculator: When Does Buying Win?

Rent versus the mortgage payment is the wrong comparison

Almost every kitchen-table version of this decision goes the same way: “rent is 2,000 a month, the mortgage would be 1,900, so buying is cheaper.” That sentence compares two numbers that are not the same kind of thing. Rent is pure expenditure — at the end of the month it is gone. A mortgage payment is two things stapled together: interest, which is gone, and principal, which moves out of your current account and into your own equity. Calling the whole payment a cost treats saving as spending.

The mirror-image error is just as common, and it is the one homeowners make: treating the whole payment as saving. Early in an amortising loan, most of it is not. Here is a single illustrative loan — 320,000 borrowed over 30 years, at an example rate of 6% chosen only to make the arithmetic legible, not because it is anyone’s current quote — with running costs at 2.2% of the property value a year and the property growing 3% a year. Every figure is an assumption you should replace with your own in the calculator above.

Two things fall out of this table. First, the monthly payment of 1,919 was never the cost of owning — the real unrecoverable figure in year 1 is 2,346 a month, because maintenance, tax and insurance are not in the payment at all. Second, the share that is genuinely saving climbs from 17% of the payment in year 1 to 39% by year 15, so the same payment buys you steadily more. That drift is why the answer changes with how long you stay. If the mechanics are new to you, our guide to how loan amortization works walks through the same split month by month.

Now notice what the renter is doing over the same fifteen years. Rent that starts at 2,000 a month and rises 3% a year reaches roughly 3,025 a month by year 15. The owner’s unrecoverable cost barely moved — 2,346 to 2,304 — because the interest portion shrinks about as fast as running costs grow. That crossing is the real mechanism behind “buying wins if you stay long enough”: the owner has largely fixed the biggest line item and the renter has not. It is also why a short holding period flips the answer so decisively.

The deposit is not free money

The second thing most comparisons skip is the largest single number in the whole decision. A deposit is not spent, so it feels costless — but it is a lump of capital you have moved out of everything else it could have been doing. So are the buying costs, which really are spent. On the example above that is 80,000 of deposit plus 12,000 of buying costs: 92,000 of capital committed on day one.

A renter who invests that 92,000 at an assumed 5% a year has about 149,900 after ten years — roughly 57,900 of growth that the buyer implicitly gave up in exchange for house-price growth on a larger, leveraged asset. That is the honest trade: leveraged exposure to one property in one city, versus unleveraged exposure to whatever the renter invests in. Neither is obviously better, and the calculator lets you set both growth rates because your view on them, not ours, should drive the answer.

The tool goes one step further and keeps investing the difference. In any year where owning costs more out of pocket than renting, the renter is assumed to invest that gap too. This is the assumption that most competitor calculators quietly omit, and omitting it flatters buying by a wide margin. It also cuts both ways: in the later years, when rent has overtaken the owner’s outlay, the renter has nothing extra to invest and the gap starts closing in the owner’s favour.

Why buying needs time: the costs at both ends

Buying a home carries a large one-off cost at purchase and another at sale, and both are pure loss. Broadly, buying costs run in the low single digits of the purchase price and selling costs somewhat higher — the calculator defaults to 3% and 5%, which are plausible middles rather than facts about your situation. Together that is a hole of roughly 8% of the value that price growth has to fill before you are level, and it is why buying and selling inside two or three years so often loses even in a rising market.

What sits inside those percentages varies enormously by country and even by state, province or city, so we deliberately quote no rates here. The transfer tax alone can be anywhere from negligible to the single largest line, and it is often tiered, and often different for first-time buyers or additional properties. Get your own figure from the authority that actually sets it:

• United States— closing costs and recording or transfer taxes are set at state and county level; your lender must give you a Loan Estimate and Closing Disclosure under the Consumer Financial Protection Bureau’s rules. Property tax comes from the county assessor.
• United Kingdom — Stamp Duty Land Tax in England and Northern Ireland (HMRC), Land and Buildings Transaction Tax in Scotland (Revenue Scotland), Land Transaction Tax in Wales (Welsh Revenue Authority). All are banded and all have their own official calculators.
• Canada — provincial land transfer tax, with separate municipal tax in some cities and rebates in some provinces. Check the provincial ministry of finance.
• Australia — stamp duty is a state tax; each state and territory revenue office publishes its own scale and concessions.
• India— stamp duty and registration charges are set by each state, and differ within a state by property type and sometimes by the buyer’s gender.

Do the same for the ongoing side. The 1% a year for maintenance and 1.2% for tax and insurance in the defaults are common rules of thumb, not measurements. An old detached house with a large garden and a new flat with a service charge behave nothing alike, and property tax varies by an order of magnitude between jurisdictions. If any of these inputs is guessed, treat the break-even year as a range rather than a date.

What moves the break-even, and in which direction

Rather than run the calculator blind, it is worth knowing which lever does what. Change one input at a time and watch the highlighted break-even row move.

The two levers people underestimate are the investment return and the transaction costs. Moving the assumed return by two percentage points can shift the break-even by several years on its own, because it compounds against the buyer for the entire window. And the transaction costs are not a percentage — they are a fixed hole dug on day one, which is why the answer is so sensitive to how long you stay.

How to use this without fooling yourself

1. Use your actual rent and an actual listing. Not the average rent in your country and not a house you like the look of — the specific flat you would keep renting and the specific home you would buy. Rent-vs-buy is a local question and national figures answer nothing.
2. Set the window to how long you will really stay. Be honest about jobs, relationships and children. If there is a realistic chance of moving in three years, run three years as well as ten and see whether the answer survives.
3. Look up your own transaction costs. Use the official calculator for your jurisdiction rather than the 3% and 5% defaults. In a high-transfer-tax city this single change can move the break-even by years.
4. Run the pessimistic case. Try house-price growth below rent growth, or below zero. If buying only wins on optimistic growth assumptions, what you have is a bet on the housing market, not a cost saving — which may still be a bet you want to make, but you should know that is what you are doing.
5. Check you can afford the payment at all. The break-even year is irrelevant if the monthly cost is unsustainable. Our mortgage calculator and the guide to how much house you can afford cover that side; if you are choosing a term, see 15 vs 30 year mortgages.

What this model deliberately leaves out

Every rent-vs-buy model is a simplification, and it is more useful to say which simplifications than to pretend there are none. This one ignores three things that differ so sharply between countries that building them in would make the tool wrong for most of its users: tax relief on mortgage interest, which exists in some countries and not others; capital-gains treatmenton a main residence and on the renter’s investments, which can favour either side depending on where you live; and rent controls or regulated increases, which can make the rent-growth input meaningless. If any of these applies to you, adjust the inputs to approximate it — for example, lower the effective mortgage rate if interest is deductible for you, or lower rent growth if increases are capped.

It also assumes a fixed rate for the whole term, steady growth rates rather than the lumpy reality of housing markets, no periods of vacancy or moving costs on the renting side, and no major one-off repairs beyond the annual maintenance percentage. Growth rates you enter are assumptions, not forecasts, and nothing about past property or market returns guarantees future ones.

Finally, the largest inputs are not financial at all. Security of tenure, the freedom to redecorate, the freedom to leave at two months’ notice, proximity to schools or family, and how much you would worry about a repair bill are all real and none of them appear in the table. Plenty of people are better off renting on the numbers and right to buy anyway, and the reverse is equally true. This page exists to tell you what the money does — not which life to choose.

This is general information, not financial advice. Figures shown are illustrative assumptions, not quotes or forecasts, and tax and transaction costs differ by country and city. Speak to a qualified adviser or mortgage broker in your own jurisdiction before committing to a purchase.

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