About the House Affordability calculator
This house affordability calculator estimates the highest home price your budget supports under common lender debt-to-income (DTI) limits. It looks at your income, your existing monthly debts and your down payment, then works backward from the largest housing payment you qualify for.
The result includes the loan amount, your down payment as a percent of the price, and the monthly principal and interest, property tax and insurance at that price. You also see both DTI caps so you know which one is holding you back. The step-by-step working shows the math with your numbers.
How to use it
- Enter your Annual household income before taxes and your Monthly debt payments.
- Enter the Down payment saved, the Interest rate and the Loan term.
- Add Property tax as a yearly percent of price and Home insurance per year.
- Choose Debt-to-income limits: Conservative 28/36, FHA-style 31/43 or Aggressive 36/45.
- Read the maximum home price and check which limit is the binding one.
The formula
First the calculator finds the most you can spend on housing each month:
Housing cap = monthly income × front-end %Total-debt cap = monthly income × back-end % − debtsMax payment = the smaller of the two
Then it solves for the price where principal and interest, tax and insurance add up to that payment:
Price = (payment − insurance ÷ 12 + down × k) ÷ (k + tax% ÷ 12)
- k — payment factor
r ÷ (1 − (1 + r)^−n), the monthly payment per dollar borrowed - r — monthly interest rate, n — number of months
- down — down payment saved; loan = price − down
Front-end and back-end ratios explained
Lenders look at two ratios. The front-end ratio is your housing payment divided by gross monthly income. The back-end ratio adds every other monthly debt, such as car loans, student loans and minimum card payments.
A long-standing guideline is 28/36: housing up to 28% of income and total debt up to 36%. FHA-style limits of 31/43 and more aggressive 36/45 settings let you borrow more, but leave less room in your budget. Actual approvals depend on the loan program, credit score and reserves.
With $100,000 of income and $500 in debts, the 28% housing cap is $2,333 a month and the 36% total cap leaves $2,500, so the housing cap binds. If your debts were higher, the back-end cap would become the limit, and paying off a car loan could raise your price more than a bigger raise would.
What this estimate leaves out
The calculator includes principal, interest, property tax and insurance. It does not add PMI, HOA dues, closing costs or the cash you may want in reserve. When your down payment is under 20%, it reminds you that PMI would lower the affordable price somewhat.
Treat the result as a ceiling, not a target. Qualifying for a payment is different from being comfortable with it once utilities, upkeep and savings goals are counted. Once you have a price in mind, run it through the mortgage calculator to see the full monthly cost with PMI and HOA, and check your debt-to-income ratio on its own. Lenders make the final call, so use this as a planning estimate.
Frequently asked questions
How much house can I afford on my salary?
Enter your income, debts and down payment and pick a DTI limit. The calculator returns the price whose payment fits within both caps.
What is the 28/36 rule?
It is a common guideline that housing costs stay under 28% of gross monthly income and all debt payments under 36%.
Does a bigger down payment increase how much I can afford?
Yes. Every dollar of down payment adds a dollar to the price without adding to the loan payment, though property tax on the higher price uses up a little of your budget.
Why is the result lower than my pre-approval?
Lenders may use higher DTI limits or different tax and insurance estimates. Try the FHA-style or Aggressive setting to compare.
Does the calculator include PMI?
No. It notes when your down payment is below 20%, which usually means PMI would apply and slightly reduce the price you can afford.
Last updated October 24, 2026. Results are estimates for education and planning — see our disclaimer.