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Mortgage Affordability Calculator

How much house you can afford is really a question about monthly payments, not price. Lenders answer it with the 28/36 rule: housing should stay under 28% of your gross monthly income, and all debt together under 36%. This mortgage affordability calculator applies that rule to find your maximum monthly housing payment, then works backwards through the loan formula to a maximum loan and home price. It also shows the more conservative 25%-of-take-home-pay rule for comparison, because qualifying for a payment and comfortably living with it are not the same thing.

Calculate

Default result: $413,613.22

Your total monthly income before taxes.

Car loans, student loans, minimum card payments — not housing.

Your net pay after taxes — used for the 25% rule comparison.

Cash you plan to put down.

Mortgage Affordability Calculator · Materials

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Max home price (28/36 rule)

$413,613.22

8000 × 500 × 6000 × 6 × 30 × 40000

Shopping list

Max loan amount (28/36 rule)
$373,613.22
Max monthly housing payment
$2,240.00
Max home price (conservative 25%-of-take-home rule)
$290,187.42

Est. total

$413,613.22

Estimate — confirm w/ supplier · calculators.dev

$413,613.22

This calculator provides estimates for general informational purposes only and is not financial, investment, tax, or legal advice. Results are projections based on the figures you enter and the stated assumptions, and actual outcomes will differ. Consult a qualified financial professional before making borrowing, saving, or investment decisions.

Reviewed by the calculators.dev team · Last updated 2026-06-24

Formula reviewed against The 28/36 debt-to-income guideline as published by lenders / consumer-finance references

How to calculate

Enter your gross monthly income, your other monthly debt payments, your take-home pay, the interest rate, term, and planned down payment. The calculator takes the lower of 28% of gross income and 36% of gross income minus your other debts — that is your maximum housing payment. It then inverts the loan-payment formula to find the largest loan that payment supports and adds your down payment for the home price. The 25% rule applies a quarter of your take-home pay the same way, as a more cautious benchmark.

Front-end cap = 0.28 × gross monthly income. Back-end cap = 0.36 × gross monthly income − other monthly debts. Max housing payment = the smaller of the two. Max loan = payment × ((1 + i)^n − 1) / (i(1 + i)^n), the inverse of the payment formula, where i is the monthly rate and n is months. Max home price = max loan + down payment. The 25% alternate uses 0.25 × take-home pay as the payment instead.
Example calculation

On $8,000 gross monthly income, the 28% rule caps housing at $2,240 a month and the 36% rule caps total debt at $2,880; with $500 of other debts, the binding limit is $2,240. At a 6% rate over 30 years that payment supports a loan of about $373,613, so with a $40,000 down payment the home price is roughly $413,613. The more conservative 25%-of-take-home rule (25% of $6,000 = $1,500) points to about $290,187 instead.

maxHomePrice
$413,613
maxLoan
$373,613
maxMonthlyPayment
$2,240
maxHomePrice25
$290,187

Assumptions

  • The 28/36 ratios are a widely used lender guideline, not a guarantee of approval — individual lenders and loan programs vary.
  • The housing payment is treated as principal and interest; taxes, insurance, and PMI would lower the price you can actually support.
  • Income and debts are entered as stable monthly figures; irregular income needs a more cautious estimate.

Common mistakes

  • Borrowing to the maximum the 28/36 rule allows, leaving no room for taxes, insurance, maintenance, or savings.
  • Forgetting that property taxes and insurance are part of the real housing payment, which shrinks the affordable price.
  • Using gross income for the 25% rule — that benchmark is based on take-home (net) pay.

Frequently asked questions

What is the 28/36 rule?

A lender guideline: keep housing costs under 28% of gross monthly income (the front-end ratio) and total debt payments under 36% (the back-end ratio). The lower of the two limits sets your maximum housing payment.

Why show a 25% rule as well?

The 28/36 rule is what lenders allow; the 25%-of-take-home rule is a more conservative comfort benchmark. Seeing both helps you separate the maximum you can borrow from an amount that leaves breathing room.

Does this guarantee I will be approved?

No. Approval also depends on credit score, employment history, the loan program, and the property. Treat this as an estimate of the price range to shop in, then get a pre-approval.

Should I include taxes and insurance?

This tool sizes the principal-and-interest payment. Because taxes, insurance, and PMI are part of your real monthly cost, the comfortable price is usually somewhat below the figure shown here.

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