Before you fall in love with a listing, figure out the number that actually fits your budget. Affordability is about the whole monthly payment and your other debts, not just the loan amount.
Lenders lean on two ratios. The first says your total housing payment should stay near 28% of your gross monthly income. The second, the back-end ratio, says all your debt payments together, housing plus car loans, student loans, and minimum credit-card payments, should stay under about 36%. Some loan programs allow higher, but 28/36 is a safe target that leaves breathing room.
A mortgage quote shows principal and interest, but your real monthly cost includes property taxes, homeowners insurance, and often private mortgage insurance if your down payment is under 20%. Add homeowners-association dues if the property has them. Together these can add hundreds of dollars a month, so budget for the full PITI, not the teaser number.
A bigger down payment lowers the loan, the monthly payment, and often removes mortgage insurance, which raises the price you can afford. But do not drain your savings to hit 20%. Keep an emergency fund and money for closing costs and moving. A smaller down payment with cash in reserve is often safer than a big one that leaves you empty.
The interest rate and loan length reshape the monthly number. A lower rate or a longer term lowers the payment and lifts your price ceiling, while a shorter term raises the payment but saves interest. Run the same price at a few rates so a small rate move does not blow your budget.
Qualifying for a payment is not the same as being comfortable with it. Factor in utilities, maintenance, and the life you want to keep living. A house that passes the ratios but leaves nothing for savings or fun is a house that causes stress.
Estimate your comfortable price in a minute with the affordability calculator, then check the full monthly cost with the main mortgage calculator. Learn how lenders read your ratios in debt-to-income explained.