Check housing and total debt against the 28% and 36% US mortgage underwriting caps.
Before tax. Use household income if you are applying jointly.
Principal + interest + taxes + insurance (+ HOA if your lender counts it).
Car, student, credit-card minimums and similar recurring debts.
If your HOA is not already inside the housing figure, add it here; it is counted as housing in this check.
US mortgage underwriting guideline only — not a lender rule. Lenders vary, and this ignores credit, reserves, property type and other underwriting factors.
front-end ratio (housing ÷ income)
How to use this tool
Type your gross (pre-tax) monthly income — joint income if you are applying jointly.
Type principal, interest, property taxes and homeowner's insurance (PITI), plus HOA dues if your lender counts them.
Type the monthly minimums on car loans, student loans, credit cards and any other recurring debts.
The front-end ratio tests housing alone against 28%; the back-end ratio tests all debts against 36%. Passing both is the guideline outcome.
Formula & worked example
Worked example: gross monthly income $8,000, housing $2,000, other debts $500. Front-end = 2,000 ÷ 8,000 = 25.0%; back-end = 2,500 ÷ 8,000 = 31.25%. Both pass: max housing at 28% is $2,240 (headroom $240) and max total debt at 36% is $2,880.
Limitations — read this before you rely on it
This is a US underwriting guideline, not a lender rule or a guarantee of approval. Many lenders allow higher ratios with compensating factors (strong credit, reserves, low loan-to-value), and some programmes use different caps. It also ignores credit score, employment history, reserves and property type.
Frequently asked questions
A US mortgage underwriting guideline: housing costs should be no more than 28% of gross monthly income, and total monthly debts no more than 36%. It is a guideline lenders often start from, not a law.
Principal, interest, property taxes and homeowner's insurance — PITI. HOA dues are often counted too, which is why this calculator has a separate HOA field.
Possibly. Lenders can approve higher ratios with compensating factors such as a high credit score, large cash reserves or a low loan-to-value ratio, and some loan programmes have their own limits.
Gross — income before tax. That is the standard for this guideline, even though your take-home pay is what you actually live on.
No. It checks only these two ratios. Credit, employment, down payment, property appraisal and the lender's own overlays all matter too.