How to use the Home Affordability Calculator
- Enter your gross (pre-tax) annual household income and the minimum monthly payments on all debts (car, student loans, cards).
- Add the cash you have for a down payment and the mortgage rate you expect.
- Include property tax, insurance and HOA so the payment matches what you would really pay.
- Pick a debt-to-income rule: 28/36 is the classic conventional guideline, 31/43 matches FHA limits.
How it works
Lenders cap two ratios. The front-end ratio limits housing costs (principal, interest, taxes, insurance, HOA) to a share of gross monthly income; the back-end ratio limits housing plus all other debt payments.
Max housing payment = min(income × front%, income × back% − other debts)The calculator then solves the mortgage formula backwards to find the home price whose full monthly payment equals that limit, given your down payment, rate and term.
Frequently asked questions
What is the 28/36 rule?
Spend no more than 28% of gross monthly income on housing costs and no more than 36% on all debt payments combined. Many lenders approve higher ratios, but 28/36 keeps a comfortable margin.
Does a bigger down payment let me afford more?
Yes. Every dollar of down payment adds a dollar to the price you can buy without increasing the loan, and 20% down also avoids PMI on a conventional loan.
Should I buy the maximum I qualify for?
Not necessarily. The maximum leaves little room for savings, repairs or job changes. Many buyers target a price 10–20% below their limit.