Mortgage Affordability Calculator
Find out how much house you can afford. Enter income, debts, down payment and rate to see your max monthly payment, loan amount and home price using the 28/36 rule.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the 28/36 rule & steps
How the Mortgage Affordability Calculator Works
This calculator estimates how much house you can afford using the lending industry’s 28/36 rule. It takes your income and debts, finds the maximum monthly payment a lender is likely to approve, then works backward through the mortgage formula to a maximum loan amount and maximum home price.
Enter your gross annual income, your existing monthly debt payments, your planned down payment, the interest rate, the term, and your estimated monthly taxes and insurance.
The Formula
Front-end limit = 28% × gross monthly income Back-end limit = (36% × gross monthly income) − monthly debts Max housing payment = the lower of the two
After subtracting taxes and insurance, the remaining payment is converted into a loan amount using the standard mortgage formula, and the down payment is added to get the maximum home price.
Worked Example
For $120,000 income, $600 in monthly debts, $60,000 down, 6.8% APR, 30 years, and $500 monthly taxes and insurance:
- Monthly income = 120,000 ÷ 12 = $10,000
- 28% rule → $2,800; 36% rule → $3,600 − $600 = $3,000
- The 28% front-end limit is lower, so max payment = $2,800/mo
- After $500 taxes/insurance, $2,300 supports a loan of about $352,800
- Plus the $60,000 down payment → roughly a $412,800 home
Front-End vs Back-End Ratios
| Ratio | What it covers | Conventional guideline |
|---|---|---|
| Front-end | Housing payment only | ≤ 28% of gross income |
| Back-end | All debt incl. mortgage | ≤ 36% of gross income |
Some loan programs allow higher ratios — FHA loans often permit a back-end ratio up to 43% or more with strong compensating factors. Treat the 28/36 result as a conservative starting point and confirm your limits with a lender.
Frequently asked questions
How much house can I afford?+
A common guideline is the 28/36 rule: spend no more than 28% of your gross monthly income on housing and no more than 36% on total debt. Take the lower of those two limits as your maximum monthly payment, subtract taxes and insurance, then work out the loan that payment supports and add your down payment.
What is the 28/36 rule?+
The 28/36 rule is a lending guideline. Your housing payment (the front-end ratio) should be at most 28% of gross monthly income, and your total monthly debt including the mortgage (the back-end ratio) should be at most 36%. Lenders use these debt-to-income ratios to decide how much you can borrow.
Does my down payment affect how much house I can afford?+
Yes. Your income and debts cap the loan amount you can carry, but the home price you can afford equals that maximum loan plus your down payment. A larger down payment raises the price you can buy and may also lower your rate and remove private mortgage insurance.
Should I include property taxes and insurance?+
Yes, because lenders qualify you on the full PITI payment (principal, interest, taxes and insurance). This calculator subtracts your monthly taxes and insurance from the maximum payment before working out the loan, so the result reflects what you can realistically borrow.
Is the maximum amount how much I should borrow?+
Not necessarily. The 28/36 rule shows the most a typical lender will approve, not a comfortable budget. Many buyers choose a payment well below the maximum to leave room for savings, emergencies, maintenance and lifestyle costs that the ratios do not capture.