What This Calculator Actually Answers
"Should I rent or buy?" isn't really one question — it's three questions wearing a trench coat: Can I afford it, will I come out ahead financially, and does it fit my life for long enough to matter? This calculator only answers the middle one, and it answers it the way a spreadsheet-minded friend would: by running the numbers for both paths side by side and telling you, in dollars, where they cross.
Concretely, it takes the home you're considering and the rental you'd otherwise choose, then simulates every year of your chosen time horizon twice. In the "buy" simulation, you make a down payment, pay closing costs, make mortgage payments, and slowly build equity as the loan balance shrinks and (assuming the market cooperates) the home's value grows. In the "rent" simulation, you keep renting — with rent rising every year — and instead of a down payment sitting in a house, that same cash sits in the market, compounding at whatever return you tell it to assume. Whenever owning costs more in a given month than renting would, the difference gets invested too. At the end, both paths are converted into a single net-worth number, and you can see exactly which year (if any) buying overtakes renting.
This is the calculation lenders, financial planners, and serious buyers actually use — not the oversimplified "rent is throwing money away" argument you'll hear at a dinner party. Renting isn't throwing money away any more than buying is; both are just different ways of paying for shelter and allocating capital, and the right call depends entirely on your numbers, not a slogan.
How to Use the Rent vs Buy Calculator
You don't need every number to be perfect — you need every number to be honest. Here's what to plug in and where to find it if you're not sure:
1. Home price and down payment
Use an actual listing price if you have one, or a realistic median for the neighborhood you're considering. For the down payment, enter what you'd genuinely put down — not the 20% textbook figure if you'd really put down 5% or 10%. If you're still building that fund, the Down Payment Calculator can help you map out a savings timeline first. A smaller down payment changes both your monthly payment and how much cash the "rent and invest" side of the comparison has to work with.
2. Mortgage rate and term
Use a rate you've actually been quoted, or a current average for your credit profile and loan type. The difference between 6% and 7.5% on a 30-year loan is not cosmetic — it can shift the breakeven year by several years on its own.
3. Monthly rent and rent growth
This should be the rent for a home comparable to the one you'd buy, not your current below-market rent if you've been in a rent-controlled or long-term unit. Rent growth of 3% a year is a reasonable national default, but fast-growing metro areas have run hotter than that for years at a stretch.
4. Appreciation, investment return, and time horizon
These three assumptions do more work than any other inputs, so it's worth entering a couple of different scenarios rather than trusting one run. Try a conservative appreciation rate (2–3%) alongside a more optimistic one (4–5%), and do the same for investment return. The horizon matters just as much — a 3-year horizon and a 15-year horizon can produce completely different verdicts on the exact same property.
5. Read the breakeven year, not just the final number
The headline result tells you who wins at your chosen horizon, but the year-by-year table underneath tells you the more useful thing: how close the race actually is, and how sensitive the outcome is to leaving a year or two earlier or later than planned.
The Math Behind the Numbers
Nothing here is a black box — every formula is standard, published finance math. Here's exactly what's running behind the scenes.
Monthly mortgage payment (principal & interest)
M = P × [ r(1+r)^n ] / [ (1+r)^n − 1 ]
Where P is the loan principal, r is the monthly interest rate, and n is the total number of monthly payments. This is the same amortization formula every mortgage lender uses, so the payment figure here should match a Loan Estimate almost exactly, assuming the same rate and term.
Buy-side net worth
Home equity grows from two separate sources: the portion of your mortgage payment that goes to principal (which increases every year as the loan matures) and home price appreciation. At the end of your horizon, the calculator subtracts estimated selling costs — real estate commissions and closing fees, typically the largest single expense in the entire comparison — from that equity to arrive at net sale proceeds. It then adds whatever the buy side accumulated in its own side investment account: in any month where owning costs less than renting would, that difference is invested and compounds right alongside the renter's side of the comparison, the same way a below-market month gets credited to the renter. Mortgage payments also stop entirely once the loan is paid off, even if your time horizon runs well past the loan term — a 15-year mortgage held over a 30-year horizon shows $0 in mortgage cost for the final 15 years, with equity and the buy-side investment account doing all the work.
Rent-side net worth
The renter's down payment and closing costs — money a buyer would have tied up in a house — are assumed to be invested instead, growing at your specified return. On top of that, any month where owning would have cost more than renting, the difference is treated as additional savings and invested too. This is the piece people most often forget to model, and it's usually the difference between "renting looks scary" and "renting is actually a reasonable financial decision" in high-price, low-rent markets.
Two worked examples
Example A — the default, balanced-market scenario. A $420,000 home, 20% down ($84,000), 6.5% rate over 30 years, against $2,100/month rent growing 3% annually, with 3.5% appreciation and a 7% investment return, at a 10-year horizon: renting wins, but narrowly — a net worth advantage of roughly $26,000 (rent net worth ≈ $298,000 vs. buy net worth ≈ $272,000). Buying doesn't overtake renting within the 10-year window under these assumptions, but it's close enough that a slightly higher appreciation rate or a lower rent would flip it.
Example B — a high rent-to-price ratio changes the outcome quickly. Keep every other input the same, but raise rent to $3,500/month — a rent-to-price ratio well above the range typically considered favorable to renting. Buying overtakes renting by year 2 and finishes the 10-year horizon roughly $247,000 ahead (buy net worth ≈ $441,000 vs. rent net worth ≈ $194,000). Once the monthly cost of owning drops meaningfully below rent, that gap compounds in the buyer's favor every month it persists.
Example C — a longer horizon widens the gap further. Lower the mortgage rate to 5%, lower the investment return assumption to 4% (a more conservative, bond-like return), keep rent at $3,500/month, and extend the horizon to 20 years: buying is already ahead by year 2 and finishes with a net worth advantage of roughly $1,033,000 (buy ≈ $1,248,000 vs. rent ≈ $215,000). This is the honest picture: buying tends to win by a wide margin when mortgage rates are low, rents are high relative to the purchase price, and the horizon is long enough for principal paydown and appreciation to compound — not automatically, and the margin narrows fast if any of those three assumptions moves against it.
Try all three scenarios yourself in the calculator above — the swings between them are the clearest illustration of why there's no universal answer, only an assumption-specific one.
Understanding the breakeven year
The breakeven year is the point where the buy-side net worth line crosses above the rent-side line on the chart. Before that point, renting and investing the difference has actually built more wealth; after it, homeownership has. If your chart shows no crossover within your horizon, that's not a calculator error — it means renting wins at every point you tested, which is a completely normal outcome in expensive coastal and gateway cities with comparatively cheap rent.
Tips for Best Results
- 💡 Rent-to-price ratio matters more than either number alone. Divide annual rent by home price. Below roughly 5%, renting tends to be strongly favored — but as Example B above shows, even a high ratio (8%+) doesn't guarantee buying wins on its own. Your investment return assumption matters just as much; a high rent-to-price ratio combined with a high investment return assumption can still favor renting.
- 💡 Factor in how long you'll actually stay. Buying rarely wins if you move within 2–3 years — closing costs and selling costs eat most of the early equity gained, regardless of how good the mortgage rate is.
- 💡 Job mobility changes the math. If a career move in the next few years is plausible, weight the shorter end of your horizon more heavily — the breakeven year matters far more than the 10- or 20-year endpoint if you might not be there that long.
- 💡 Run the numbers twice, once conservative and once optimistic. Because appreciation and investment return are assumptions, not facts, testing a low and a high scenario tells you whether your decision is robust or whether it only "works" under rosy assumptions.
Common Mistakes to Avoid
- ⚠️ Ignoring opportunity cost. A down payment invested in the market can compound significantly over a decade. Comparing buying against "renting and doing nothing with the cash" isn't a fair fight — always model a realistic investment alternative.
- ⚠️ Underestimating maintenance. Budget 1–2% of home value annually for repairs and upkeep. Deferred maintenance is a real cost that renters simply never pay — it just doesn't show up on a mortgage statement.
Frequently Asked Questions
Is it better to rent or buy a home financially?
It depends on how long you plan to stay, local rent-to-price ratios, mortgage rates, and what you'd do with the money otherwise spent on a down payment. This calculator compares net worth under both scenarios over your chosen horizon so you can see your specific breakeven point.
What is the breakeven point in a rent vs buy comparison?
It's the year in which buying's total net financial position overtakes renting, once closing costs, equity, appreciation, and opportunity cost are all accounted for.
Does this calculator include opportunity cost?
Yes. If you rent, the money you would have used for a down payment and closing costs is assumed to be invested and grow at your specified investment return rate.
What costs are included on the buying side?
Mortgage principal and interest, property taxes, homeowners insurance equivalent, maintenance, HOA fees, closing costs, and selling costs at the end of the horizon, net of appreciation and equity paid down.
What costs are included on the renting side?
Monthly rent with your specified annual growth rate, compared against the investment growth of the capital you didn't spend on a home purchase.
Why does the calculator say renting wins even though "rent is throwing money away"?
Because that phrase isn't really true. Rent pays for shelter the same way a mortgage payment does — the difference is what happens to the cash you'd otherwise tie up in a down payment. In markets where rent is cheap relative to home prices, investing that cash can outgrow home equity, especially once closing costs, maintenance, and selling costs are factored into the buying side.
How much does moving early change the outcome?
Substantially. Closing costs and selling costs are largely fixed regardless of how long you own, so they're spread over fewer years if you sell early — which is why buying rarely looks good on a 2–3 year horizon even in markets where it clearly wins over 10 years.
Should I use a national average or my local market's numbers?
Always your local numbers if you can get them. Rent-to-price ratios, appreciation trends, and even typical closing cost percentages vary enough between cities — and even between neighborhoods — that a national average can point you toward the wrong conclusion for your specific decision.
Does this account for tax benefits of homeownership?
Not directly — mortgage interest and property tax deductions depend on your specific tax situation, filing status, and whether you itemize, which varies too much to model generically. If those deductions matter meaningfully to you, treat the calculator's buy-side result as slightly conservative.