Home Affordability Calculator 2026 - How Much House Can I Afford?

The HomeBuyerMath affordability calculator estimates the maximum home price you can responsibly purchase based on your income, existing monthly debt payments, available down payment, and prevailing interest rates. It uses the same 28/36 debt-to-income (DTI) framework that mortgage underwriters apply during pre-approval, so the result closely tracks what a lender would actually offer.

How the 28/36 Rule Works

The 28/36 rule has two ceilings. The front-end ratio caps your housing payment (PITI plus HOA) at 28% of your gross monthly income. The back-end ratio caps your total monthly debt — housing payment plus car loans, student loans, credit card minimums, child support, and other recurring obligations — at 36% of gross income. Conservative lenders enforce both; aggressive lenders may stretch the back-end to 43% or 50% for FHA and qualified mortgages, but doing so increases the risk of becoming house-poor. The calculator solves backward from these ratios to find the maximum loan amount, then adds your down payment to derive the maximum home price.

Inputs and Outputs

Inputs include annual household income, monthly debts, available cash for down payment and closing, target loan term, expected interest rate, estimated property tax rate, and homeowner's insurance. The output shows the maximum home price you qualify for, the corresponding monthly PITI, your front-end and back-end DTI at that price, and a stretch scenario at 36/43 ratios for context. The tool also flags when PMI applies (down payment below 20%) and adjusts the estimated payment accordingly.

Next Steps

Once you know your range, run specific scenarios in the mortgage payment calculator, estimate upfront cash needs in the closing costs calculator, and review state-specific data such as property tax rates and down payment assistance programs in the state guides.