Rent vs buy: what every calculator input means and how to set it

Short answer: a rent-vs-buy calculator compares the total cost of owning — payment, taxes, insurance, maintenance, and buying and selling costs, minus equity built — with the total cost of renting plus what the renter’s savings would earn. The result depends most on how long you’ll stay, then on appreciation and rent growth. Set those honestly and the calculator is genuinely useful.

The inputs, one by one

Home price and down payment

The price sets the loan; the down payment sets the loan-to-value and whether PMI applies. For example, a $380,000 home with 10% down at 6.75% has a P&I of about $2,218, plus roughly $348 of property tax (at 1.10% a year), $158 of insurance (0.50%) and $157 of PMI (0.55%) — about $2,882 a month in total.

Interest rate and term

Use a realistic current rate for the buyer’s credit, not the lowest advertised rate. Term is usually 30 years for this comparison.

Property tax, insurance, HOA and maintenance

These are the costs renters don’t pay directly. Maintenance is often estimated at 1% of the home’s value a year — older homes more.

Closing costs to buy and to sell

Buying costs (lender fees, title, prepaid items) are paid up front. Selling costs — commissions, transfer taxes, seller concessions — come at the end and are often 6–10% of the sale price combined. Forgetting selling costs is the classic mistake.

Monthly rent and rent growth

Use the rent for a comparable home. Rent growth matters over longer horizons; a few percent a year is a common default.

Home appreciation

How fast the home’s value rises. This is the most optimistic input on most calculators. Use a conservative figure and test a lower one.

Investment return

The renter keeps the down payment and closing costs, and may save the monthly difference. The calculator should grow that money at a stated return, otherwise renting is unfairly penalised.

Time horizon

The number of years the buyer expects to stay. Short stays rarely recover the transaction costs; long stays usually favour buying. This single input flips more results than any other.

How to read the result

A good rent-vs-buy result shows the year buying overtakes renting (if it does), and the difference in wealth at the chosen horizon. If the crossover year is beyond the buyer’s plans, renting may be the better choice for now.

How agents and loan officers should use it

Put the calculator on first-time-buyer pages with transparent default assumptions. Resist tuning inputs to make buying always win — a buyer who sees an honest “rent for another two years” answer remembers who gave it to them. End with a soft action (“Email me this comparison”) and follow up when their horizon changes.

For where this fits among other calculators on your site, see our placement guide.

Estimates only. Tax treatment depends on your situation; consult a tax professional.