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Mortgage Affordability Calculator

Estimate how much home you can afford from income, debts and a target payment.

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You could afford about
$276,874.08
Max monthly payment
$1,660

Uses a 36% debt-to-income rule of thumb. Lenders’ criteria vary.

How it works

This calculator estimates the largest mortgage you could reasonably take on, working backward from income. It applies the 36% debt-to-income (DTI) rule: no more than 36% of gross monthly income should go to debt payments of every kind — the future mortgage plus car loans, student loans and credit-card minimums. Whatever room is left after your existing debts becomes the mortgage payment budget, and the tool converts that payment into a loan amount at your rate and term.

The two formulas behind the result:

  • Maximum monthly payment = 36% × gross monthly income − existing monthly debts
  • Affordable loan = payment × (1 − (1 + r)^−n) ÷ r, where r is the monthly rate (annual ÷ 12) and n the term in months

A worked example using the defaults: on a $6,000 monthly income, 36% is $2,160. Subtract $500 of existing debt payments and the mortgage budget is $1,660 a month. At 6% over 30 years (r = 0.005, n = 360), that payment amortizes a loan of about $276,874.08. The result is a loan, not a house price — add your down payment to set the price: with 20% down, this example supports a purchase around $346,000.

Read the number with the full 28/36 rule in mind. Its other half caps housing costs alone at 28% of income, and lenders count property taxes, homeowners insurance, PMI and HOA dues inside that housing figure — none of which this tool models. Because the $1,660 here is pure principal and interest, the loan a lender actually approves on the same income is usually smaller. Treat the output as a ceiling rather than a target, and keep cash aside for closing costs and maintenance.

Estimates only — actual approval depends on credit score, down payment, documented income and each lender’s own DTI limits. Confirm real numbers with a lender before making offers.

Frequently asked questions

What rule does this calculator use?
It applies the 36% debt-to-income (DTI) guideline: all monthly debt payments, including the new mortgage, should stay under 36% of gross monthly income. That is the back-end half of the classic 28/36 rule used in conservative mortgage underwriting. Many lenders will approve DTIs up to 43–50% on qualified mortgages, so treat 36% as a prudent ceiling rather than a hard limit.
What is the difference between the 28% and 36% limits?
The 28% front-end ratio caps housing costs alone, while the 36% back-end ratio caps housing plus every other debt. This tool applies only the 36% test and subtracts your existing debts from that ceiling. If you carry no other debt, consider capping the housing payment near 28% of income anyway to leave slack in your budget.
Is the result a home price or a loan amount?
A loan amount — the principal your maximum payment can amortize over the term you set. To turn it into a home price, add your down payment on top: with the default result of $276,874.08 and 20% down, you could shop around $346,000. A larger down payment raises the price you can target without changing the loan.
Does it include property taxes, insurance, PMI or HOA fees?
No. The maximum payment it derives is spent entirely on principal and interest, but real lenders count property taxes, homeowners insurance, mortgage insurance and HOA dues inside your debt-to-income ratio. Those items commonly add hundreds of dollars a month, so the loan a lender approves on the same income is usually smaller than this estimate.
Should I enter gross or net income?
Enter gross (pre-tax) income — that is what lenders underwrite against and what the 36% guideline assumes. If you prefer to budget from take-home pay, your personal ceiling will land below the calculator’s figure, which is a reasonable margin of safety.
How much does the interest rate change the answer?
Substantially, because the same payment finances less principal at a higher rate. At the defaults, a $1,660 payment supports $276,874.08 at 6% over 30 years but only $249,510.56 at 7% — roughly 10% less loan for one extra percentage point. Re-run the numbers whenever quoted rates move.
Is my financial data uploaded?
No — the calculation runs entirely in your browser and nothing you type is sent to a server.

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