About this tool
House Affordability Calculator is a free, in-browser tool that estimates the maximum home price and loan you can afford from your annual income, monthly debts, down payment, interest rate and loan term. Nothing is uploaded — every figure is computed locally as you type.
It uses the standard lender debt-to-income (DTI) method: your affordable monthly payment is the lower of the front-end limit (housing share of gross monthly income, default 28%) and the back-end limit (all debt share, default 36%) minus your existing monthly debts. That payment is then converted into a maximum loan with the amortization present-value formula PMT·(1−(1+r)^−n)/r, and the down payment is added to get the price.
Use it before house hunting to set a realistic price ceiling, or adjust the DTI sliders to match a specific lender's rules or a more conservative personal budget.
Frequently asked questions
What are front-end and back-end DTI ratios?
The front-end ratio caps your housing payment as a share of gross monthly income (classic 28%); the back-end ratio caps all debt payments combined (classic 36%). The calculator takes whichever limit gives the smaller payment, after subtracting your existing monthly debts from the back-end allowance.
Does the payment include property tax and insurance?
No — the affordable payment here is modeled as principal and interest only, with the rate treated as annual and compounded monthly (rate ÷ 12). Real lenders count taxes, insurance and HOA fees inside the same DTI limits, so treat the result as an upper bound and leave headroom for those costs.
Why do I get an error about my debts?
If your existing monthly debt payments already use up the entire back-end allowance (gross monthly income × back-end % minus debts ≤ 0), no mortgage payment fits, so the tool reports it instead of showing a misleading number.
Is my financial data private?
Yes. The calculator runs 100% in your browser — no income or debt figures are sent to any server, and nothing is stored after you close the page.
More tools