Start with the price-to-rent ratio
The price-to-rent ratio is the fastest sanity check on whether a market leans toward renting or buying. Divide the price of a home by the annual rent for a comparable home in the same area: ratio = home price / (monthly rent × 12). A home priced at 15 times its yearly rent has a ratio of 15; the same home at 30 times yearly rent has a ratio of 30.
The logic is simple. A low ratio means homes are cheap relative to what they rent for, so each payment you make as an owner buys you more housing than the equivalent rent — buying tends to win. A high ratio means homes are expensive relative to rents, so you'd pay a large premium to own what you could rent cheaply, and renting (while investing the difference) tends to win.
These are tendencies, not verdicts. The ratio ignores your mortgage rate, how fast rents and prices move, taxes, and how long you'll stay — all of which can flip the result. Treat it as the opening question, not the answer. To see how ownership costs stack up across markets, the Global Mortgage Affordability Index ranks countries by how much of a median income a typical mortgage payment consumes, using the same price-to-income logic that sits behind a high or low price-to-rent ratio.
Find your break-even horizon
The single most decisive factor is how long you'll stay. Buying carries large one-time costs at the start, so ownership starts out far more expensive than renting and only becomes cheaper after enough years have passed. That crossover is your break-even point — the year at which the total net cost of owning drops below the total net cost of renting.
Before the break-even year, renting is cheaper and you'd lose money buying. After it, every additional year you stay tilts further in favour of owning. So the question 'should I rent or buy?' is really 'will I stay past my break-even year?' If you expect to move within a couple of years, renting is usually the safer math regardless of how the ratio looks; if you'll stay well beyond the crossover, buying usually wins.
Don't guess the break-even year — model it. The Rent vs Buy Calculator runs both paths side by side, year by year, and reports the first year buying becomes the cheaper option for the assumptions you supply: appreciation, rent growth, your mortgage rate, and the return you'd earn by investing the down payment instead. Change one input and watch the crossover move. That sensitivity is the point: a few percentage points of assumed price growth can shift break-even by years.
Count the costs people forget
Most rent-versus-buy regret comes from comparing rent against the mortgage payment alone. That understates owning badly. Buying carries costs that renting simply doesn't:
- Transaction and closing costs when you buy, and selling costs when you leave — both are a percentage of the price and are largely sunk. They're the main reason short stays favour renting. - Maintenance and repairs, commonly estimated at roughly 1% of the home's value per year. A renter's landlord absorbs this; an owner doesn't. - Property taxes and insurance, which scale with the home's value and never stop, even after the loan is paid off. - The opportunity cost of the down payment. That cash, if invested instead, could have earned a return. A fair comparison credits the renter with the growth on the money they didn't tie up in a deposit.
A proper comparison also gives owning its fair credit: each payment builds equity, and the home may appreciate. The Rent vs Buy Calculator nets all of this — out-of-pocket spending minus the equity you'd walk away with if you sold — so you compare true net cost, not payment against payment. Skip these forgotten costs and you'll conclude buying is cheaper years before it actually is.
Check the buy side against your income
Even when the long-run math favours buying, you still have to carry the payment month to month — and that's where deals quietly go wrong. The widely used 28/36 rule is the simplest guardrail: keep total housing costs (principal, interest, taxes, and insurance) at or below 28% of your gross income, and keep all your debt payments combined — housing plus loans and card minimums — at or below 36%. Cross those lines and the payment starts to crowd out everything else, and lenders grow cautious too.
Use the Mortgage Calculator to turn a purchase price, down payment, rate, and term into an actual monthly payment, then test it against the 28% and 36% lines. Push the down payment up or the price down until the payment fits comfortably, not just barely. The same tool shows your amortization — how each payment splits between interest and principal — and how adding extra to principal shortens the loan and cuts total interest.
If you lean toward renting, run the parallel check with the Rent Affordability Calculator, which tests your rent against the common 30%-of-income rule and shows what's left each month. Affordability on either side is about the monthly squeeze; break-even is about the long run. A sound decision needs both to line up.