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House Affordability Calculator

Find out how much house you can realistically afford based on your income, existing debts, and down payment — using the lender-standard 28/36 debt-to-income rule.

Understanding the House Affordability Calculator

A house affordability calculator estimates the home price and loan you can comfortably support based on your income, debts, down payment, and the lender's debt-to-income limits. It applies the well-known 28/36 rule: housing costs at most 28% of gross monthly income, and total debt at most 36%. It is for buyers wanting a realistic budget before they shop. The result is an estimate for planning, not a loan approval. Everything is computed in your browser, so your financial details stay private.

How it works

The tool takes your gross monthly income and multiplies it by the front-end ratio (28%) to find the maximum housing payment, and by the back-end ratio (36%) minus your existing monthly debts to find another ceiling. The lower of the two becomes your affordable PITI. It then subtracts estimated taxes and insurance to isolate principal and interest, and reverses the mortgage formula at your chosen rate and term to back out the supportable loan amount. Adding your down payment gives the target home price. Adjust the ratios, rate, or down payment to see how affordability shifts.

Max housing payment = min(0.28 x gross monthly income, 0.36 x gross monthly income - existing debts); affordable price = supportable loan (from PITI minus tax/insurance) + down payment

Worked example

Gross income of 7,000/month with 500 in existing debts. Front-end: 0.28 x 7000 = 1,960. Back-end: 0.36 x 7000 - 500 = 2,020. The binding limit is 1,960 for PITI. Subtract 350 for taxes and insurance, leaving 1,610 for P&I. At 6.5% over 30 years that supports a loan of about 254,500. With 50,000 down, you can target a home priced around 304,500. Reducing existing debts or raising the down payment increases this number.

Tips & common mistakes

  • The 28/36 rule is a guideline; some lenders allow higher ratios but the loan costs more.
  • Use gross (pre-tax) income, the figure lenders qualify you on.
  • Include all recurring debts: car loans, student loans, and minimum credit card payments.
  • Affordable does not mean comfortable; leave room for savings, repairs, and emergencies.
  • Higher interest rates shrink the loan a given payment supports, so re-check when rates move.

Sources & methodology

  • • Consumer Financial Protection Bureau — Debt-to-income ratio and the 43% rule (https://www.consumerfinance.gov)
  • • Fannie Mae — Eligibility and DTI guidelines (https://www.fanniemae.com)

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Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.

How to Use This Calculator

  1. 1Enter your annual household income and monthly debt payments.
  2. 2Add your down payment, the interest rate, and loan term.
  3. 3Click Calculate Affordability to see your maximum home price and loan.

Frequently Asked Questions

What is the 28/36 rule?

A common lending guideline: your monthly housing costs should stay under 28% of gross monthly income, and your total debt payments (housing + car + cards + loans) under 36%. This calculator uses whichever limit is lower.

What counts as monthly debt?

Recurring monthly obligations lenders count toward your debt-to-income ratio: car loans, student loans, minimum credit-card payments, personal loans, and child support. Utilities and groceries are not included.

Does this guarantee loan approval?

No. It is an estimate based on income ratios. Actual approval also depends on credit score, employment history, the loan program, and whether you need private mortgage insurance (PMI) for a down payment under 20%.

How can I afford more house?

Increase your down payment, pay down existing debts, improve your credit score for a lower rate, or choose a longer loan term (which lowers the monthly payment but increases total interest).

Does the 28/36 rule apply outside the US?

No. This calculator uses the US 28/36 debt-to-income rule. Other countries assess affordability differently: Canada uses GDS/TDS ratios (around 32% and 40%), the UK typically applies an income-multiple cap (roughly 4–4.5x annual income), and Australian lenders run a serviceability assessment with a stressed interest-rate buffer. Treat the result here as a US-oriented estimate.