🏡Mortgage Affordability Calculator

Our mortgage affordability calculator answers the central question for every home buyer: how much house can I afford? Enter your gross monthly income, existing debt payments, down payment, interest rate, and property tax rate, and the calculator applies the lending industry's qualifying ratios to show your maximum home price, estimated monthly payment, and debt-to-income breakdown in one place.

Home Affordability Calculator by Income and Debt: How Lenders Qualify Buyers

Mortgage lenders use debt-to-income ratios, commonly abbreviated as DTI, to measure how much of your gross monthly income is consumed by debt obligations. Two separate ratios matter in the mortgage qualification process. The front-end ratio, also called the housing ratio, compares your total housing costs to your gross income. Lenders traditionally cap this at 28%, meaning your monthly principal, interest, property taxes, homeowners insurance, and applicable HOA fees should not exceed 28 cents of every dollar you earn before taxes.

The back-end ratio, also called the total DTI or debt ratio, adds all other monthly debt payments to your housing costs before comparing them to gross income. Those other debts include minimum credit card payments, car loans, student loans, personal loans, and any other recurring debt obligation that appears on your credit report. Conventional loan guidelines have historically set the back-end limit at 36%, though Fannie Mae and Freddie Mac now allow up to 45% to 50% for borrowers with strong compensating factors such as large cash reserves, a high credit score, or a substantial down payment. FHA loans typically qualify borrowers at up to 43%.

The 28/36 rule is not a hard legal limit but a widely used benchmark that has withstood decades of lending history. Lenders that stretch beyond it are betting that your financial situation is more resilient than the numbers suggest. That bet does not always pay off for borrowers, which is why the traditional 36% back-end limit exists and why financial advisors often recommend targeting below it even if you qualify for more.

Maximum Mortgage Amount by Salary Calculator: What the Numbers Mean

The maximum mortgage amount is not simply a multiple of your salary. It depends on the interaction between your income, your existing debts, your down payment, the current interest rate, the loan term, and local property tax rates. All of these variables feed into the monthly payment calculation, and the lender approves a loan only when the resulting monthly payment fits within the DTI limits.

A general rule of thumb is that buyers can afford a home priced at roughly two and a half to three times their gross annual income, but this estimate becomes less accurate as interest rates rise or as existing debt loads increase. At 7% interest, a $300,000 mortgage carries a principal and interest payment of about $1,996 per month. At 4%, that same loan costs $1,432. The difference of $564 per month translates directly into borrowing power: the higher the rate, the less house the same income can support.

Your down payment size affects affordability in two ways. A larger down payment reduces the loan amount, lowering the monthly payment and keeping DTI ratios comfortably below limits. A down payment of at least 20% also eliminates private mortgage insurance (PMI), which typically costs between 0.5% and 1.5% of the loan balance per year, adding $100 to $300 or more to the monthly payment on a $300,000 loan. Eliminating PMI frees up that payment capacity for a larger loan.

How Much Mortgage Can I Qualify For: The True Cost of Homeownership

Lenders calculate how much you qualify for based on the four components of PITI: principal, interest, taxes, and insurance. But the real monthly cost of owning a home extends further than what the lender counts.

• Maintenance and repairs: Budget 1% to 2% of the home's value per year. On a $400,000 home that is $4,000 to $8,000 annually, or $333 to $667 per month on average.
• Utilities: Owned homes are often larger and older than rented units, resulting in higher heating, cooling, and water bills.
• HOA fees: Can range from $100 to over $1,000 per month for condos and planned communities, and lenders count these in your DTI.
• Closing costs: Typically 2% to 5% of the purchase price, due at closing and generally not rolled into the loan.

Borrowing the maximum amount the lender offers leaves no room for any of these additional costs without cutting into other savings. Financial planners frequently suggest targeting housing costs of 25% to 30% of take-home pay, a stricter standard than lenders use, because it leaves space for retirement contributions, emergency savings, and discretionary spending.