Home Affordability Calculator
How much house you can afford, based on the standard debt-to-income guideline lenders actually use.
Car loans, student loans, credit card minimums, etc.
Home Affordability Calculator
“How much house can I afford” isn’t really a home-price question — it’s a monthly-payment question, worked backward. Lenders use a debt-to-income (DTI) ratio to decide the maximum payment they’ll approve, then that payment (plus your down payment) determines the home price. This calculator does the same math: it finds the largest monthly payment your income and existing debts support under the standard 28/36 rule (or the more permissive FHA 31/43 guideline), then solves for the home price that payment can carry — including principal, interest, property tax, insurance, and HOA, not just the loan itself.
The 28/36 Rule (and Its FHA Cousin)
The conventional-loan guideline: your total housing payment (PITI) shouldn’t exceed 28% of gross monthly income, and your total debt — housing plus car loans, student loans, credit cards — shouldn’t exceed 36%. FHA loans use a looser 31%/43% pairing, letting buyers with lower down payments or thinner credit qualify for more house. Whichever standard you use, the calculator applies whichever ratio (front-end housing-only, or back-end total-debt) is more restrictive for your specific numbers — existing debt can shrink your housing budget below what the housing-only percentage alone would suggest.
Why PITI, Not Just the Loan Payment
A mortgage quote often only shows principal and interest, but that’s not what actually leaves your account every month. Property tax and homeowners insurance get folded into most mortgage payments via escrow, and HOA dues (where they apply) are just as real a monthly obligation. This calculator solves for a home price where all four pieces together stay within your DTI limit — property tax defaults to your state’s actual average effective rate (the same data behind this site’s Property Tax Calculator), and insurance defaults to a common 0.5%-of-home-value estimate, both editable if you have better numbers.
Example: $90,000 Income, $300/mo Debt, $20,000 Down, 6.5% Rate, 30-Year
Monthly income: $7,500. Front-end limit (28%): $2,100. Back-end limit (36%): $2,700 − $300 existing debt = $2,400. The front-end limit is more restrictive here, capping the payment at $2,100/month. After property tax, insurance, and HOA are backed out of that payment, the remaining principal-and-interest capacity — combined with the $20,000 down payment — lands the estimated max home price in the low $300,000s at these assumptions.
Frequently Asked Questions
What is the 28/36 rule?
A guideline (not a law) suggesting your monthly housing payment should stay under 28% of gross monthly income, and your total monthly debt should stay under 36%. It’s the conventional-loan baseline; actual lender limits vary and can go higher.
Why is my back-end ratio more restrictive than my front-end ratio?
If you already have significant monthly debt, that eats into the total debt ceiling before housing is even considered, which can leave less room for a mortgage payment than the housing-only limit would suggest on its own. This calculator uses whichever ratio is more restrictive for your situation.
Does this include property tax and insurance in the payment?
Yes — the affordability limit is based on full PITI (Principal, Interest, Taxes, Insurance), not just the loan payment. Property tax defaults to your state’s average effective rate; insurance defaults to a common rule-of-thumb estimate. Both are editable.
Why doesn’t this use a specific mortgage interest rate?
Mortgage rates change daily and vary by lender, credit score, and loan type — hardcoding a single “current” rate would go stale almost immediately. Enter the rate you’ve been quoted or a current estimate from a lender for the most accurate result.
This calculator provides a simplified estimate based on the standard debt-to-income guidelines described above. It does not account for private mortgage insurance (PMI) on down payments under 20%, closing costs, your credit score, or a specific lender’s underwriting rules — actual approved loan amounts vary by lender. Check with a mortgage lender for a precise pre-approval figure.
