This tool does not tell you whether owning is smarter than renting in general; it tells you which choice comes out ahead for the specific price, deposit, rate and stay length you enter, once appreciation, upkeep, selling costs and the return you'd earn by not tying up a deposit are all netted against each other. The output is a dollar gap between two simulated end states, not a moral verdict.
Reading the net-position gap
Buying's net position is the projected sale price minus a 5% selling cost, minus whatever mortgage balance is left, minus everything spent on closing, interest and upkeep along the way. Renting's net position is whatever the deposit and any monthly cash saved would have grown to, minus the total rent paid. Whichever number is higher is the better financial outcome under those assumptions, and the gap tells you by how much.
A gap under about 5% of the home price after a stay of five years or more is close to a coin flip: small changes in appreciation or the invested return will flip the winner. A gap north of 15% of the home price is a much sturdier result and less likely to be reversed by a slightly different rate assumption.
Stay length dominates the outcome more than any single rate input. Owning has large upfront frictions (closing costs, low early-year equity build) that renting avoids, so the comparison typically shifts toward buying the longer the home is held, all else equal.
Three stays, three outcomes
A four-year stay: price 520,000, deposit 100,000, rate 6.5%, appreciation 3%, upkeep 1.3%, rent starting at 2,600 and rising 3% a year, cash otherwise earning 5%. Renting wins clearly here, ending with a net position near 37,300 against buying's roughly 7,400 — the short hold barely lets equity or appreciation offset the 3% closing cost and 5% eventual selling cost.
A twelve-year stay: price 350,000, deposit 50,000, rate 6.5%, appreciation 3.5%, upkeep 1.2%, rent starting at 1,800 and rising 3.5% a year. Both paths finish negative in nominal net terms once total rent or total ownership cost is subtracted, but buying's shortfall of about 13,700 is far smaller than renting's shortfall of about 171,900, so buying is the better choice by a wide margin over that longer horizon.
An eight-year stay with a thin deposit: price 420,000, deposit only 40,000, rate 7.5%, appreciation 2.5%, upkeep 1.5%, rent starting at 2,200 and rising 4% a year, cash earning 6%. Here renting wins, ending near negative 74,900 against buying's negative 138,000 — the small deposit means most of the payment is interest for years, and low appreciation combined with a high invested return tips the balance toward renting even at eight years.
What moves the answer more than people expect
The return assumed on money not tied up in a deposit matters as much as the mortgage rate itself. Raising it from 5% to 7% while holding everything else fixed can turn a narrow buying win into a renting win, because that money compounds for the entire stay rather than being locked in illiquid home equity.
Rent growth compounds too, and small annual differences add up over a decade. A rent that climbs 5% a year rather than 3% adds tens of thousands to total rent paid over ten years even before accounting for what that extra cash could otherwise have earned invested.
Upkeep and property tax, entered here as a single annual percentage of price, quietly do a lot of work. Moving upkeep from 1% to 2% of a 400,000 home adds roughly 4,000 a year to ownership cost, which over a ten-year stay is a bigger swing than most single-point changes to the mortgage rate.
Where the model breaks down
The simulation assumes a fixed mortgage rate, steady home appreciation, steady rent growth and a steady investment return for the entire holding period. Real housing markets and real portfolios do not move in straight lines; a market correction in year two or a rent spike in year eight changes the true outcome in ways a smooth annual growth rate cannot capture.
It assumes you sell at the end of the period and pay a full 5% in agent and closing costs, which is realistic for a typical sale but too high if you plan to keep the home and rent it out, and possibly too low in markets with higher transfer taxes or agent commissions.
It does not model tax effects such as mortgage interest deductibility, primary-residence capital gains exclusions, or property tax deductions, all of which can shift the comparison meaningfully depending on your jurisdiction and whether you itemize.
It also assumes the renter actually invests every dollar of cashflow saved rather than spending it. If that discipline doesn't hold in practice, the renting outcome shown here is an upper bound, not a forecast.
Jurisdiction and timing notes
In the United States, mortgage interest and property tax are deductible only if you itemize, which fewer filers do since the standard deduction roughly doubled from 2018 onward; check your own filing status before assuming a tax benefit this tool doesn't add in.
In the UK there is no equivalent mortgage interest deduction for owner-occupiers, and most mortgages are priced as two- or five-year fixes inside a longer term, so the 'rate' entered here should reflect the fixed-period rate you'll actually pay, not a lifetime average.
Selling costs vary widely by location: US agent commissions have historically run higher than in much of Europe, while some US states and UK stamp duty add meaningfully to the buying side that this tool folds into the flat 3% closing-cost assumption. Adjust the price or deposit inputs to compensate if your local costs differ.
Run the comparison again whenever your mortgage quote changes meaningfully, since rates can move by a quarter point or more between a rate lock and closing, and that alone can swing a close result.
Frequently asked questions
- How many years do I need to stay for buying to beat renting?
- There's no universal number because it depends on the deposit, rate, upkeep and rent growth you enter, but in the scenarios above a four-year stay favored renting while a twelve-year stay at similar rates favored buying by a wide margin. Run your own numbers at a couple of different stay lengths to find the crossover point for your situation.
- Why does the tool assume the renter invests the difference?
- It's comparing net worth outcomes, not just monthly cash outflow, so it credits the renting path with whatever the deposit plus any monthly savings would have earned at the return rate you set. If you wouldn't actually invest that difference, treat the renting figure as an optimistic upper bound rather than a realistic one.
- Does this include mortgage interest tax deductions?
- No. The calculator compares pre-tax cash flows and asset values only. In the US, itemizing filers who deduct mortgage interest and property tax will see a real-world result somewhat better for buying than the raw number shown here; most filers taking the standard deduction will not.
- What selling costs does it assume, and are they realistic for me?
- It deducts 3% of the purchase price as closing costs when you buy and 5% of the projected sale price as selling costs at the end. Those are reasonable US averages for agent commission plus fees, but if you're in a market with different transfer taxes, stamp duty, or commission norms, the true buying-side cost may be higher or lower.
- Why did the same rate produce a different winner in the two long-term scenarios?
- Because rent growth, appreciation and the deposit size all moved between them too. A larger deposit relative to price shrinks the loan and its interest burden, and low appreciation paired with a higher invested return favors renting even over a long stay, so it's the combination of inputs that decides the outcome, not the rate alone.
- Should I trust the exact dollar gap, or just the direction?
- Treat the gap as an estimate rather than a precise forecast. A gap that's small relative to the home price is easily flipped by a slightly different appreciation or investment-return assumption; a gap that's large relative to the home price is a more durable signal about which choice suits your situation.
Sources
- Freddie Mac Primary Mortgage Market Survey — Weekly US average 30-year fixed mortgage rate, used as the benchmark rate range referenced for scenario inputs (data through 2025).
- IRS Publication 936, Home Mortgage Interest Deduction — Confirms mortgage interest is deductible only for taxpayers who itemize, relevant to the tax caveat above (publication for 2024 tax year, current as of 2025).
- HM Revenue & Customs — Stamp Duty Land Tax — Sets out UK property transaction tax rates, relevant to the buying-side cost caveat for UK users (guidance current as of 2025).