Debt-to-Income Ratio Calculator

There is no single regulatory number. The CFPB states plainly that different loan products and different lenders apply different DTI limits, so the honest answer is that your target depends on the program you are applying to.

For a concrete published benchmark, Fannie Mae's Selling Guide sets a maximum total DTI of 36% for manually underwritten loans, which may be exceeded up to 45% when the borrower meets the credit-score and reserve requirements in the Eligibility Matrix. Loan casefiles underwritten through Desktop Underwriter allow up to 50%.

Treat 36% as a comfortable planning target rather than a pass/fail line, and remember that clearing a lender's maximum is not the same as the payment being affordable for your household.

For years the figure quoted everywhere was 43%, because the General Qualified Mortgage definition under Regulation Z included a hard 43% DTI limit. That is no longer the test. The CFPB's General QM Final Rule removed the 43% DTI limit and replaced it with price-based thresholds: a loan meets the General QM definition when its annual percentage rate exceeds the average prime offer rate for a comparable transaction by less than 2.25 percentage points, with higher thresholds for smaller loan amounts, certain manufactured-housing loans, and subordinate liens.

The rule took effect on 1 March 2021 and its mandatory compliance date was extended to 1 October 2022. You will still see 43% cited widely, and individual lenders and investors are free to keep it as their own overlay, but it is a lender policy rather than the current General QM requirement.

This matters when you are shopping: because the current test is priced-based, a strong rate quote can carry a DTI that an older 43% rule of thumb would have told you was disqualifying.

The front-end ratio counts only housing costs against gross income. The back-end ratio counts every monthly debt payment including housing. Lenders generally weigh the back-end figure most heavily, and it is the number this calculator reports.

Enter the housing payment you will actually have. If you are applying for a mortgage, that means the proposed new payment rather than your current rent, since the new obligation is what the lender underwrites.

This calculator's math and the ratio itself are currency-agnostic — switch the currency selector to GBP and it works the same way. The published benchmarks above are US-specific, though, so they do not transfer directly to a UK mortgage application.

The Bank of England's Financial Policy Committee withdrew its mortgage affordability stress-test recommendation from 1 August 2022, but kept the separate loan-to-income (LTI) 'flow limit' in place, which restricts how many mortgages a lender can extend at an LTI of 4.5 or higher. LTI compares the loan amount to income and is not the same measurement as the monthly-payment DTI ratio this calculator reports — the UK does not publish a single DTI ceiling the way the US General QM framework once did.

In place of the withdrawn stress test, the FCA's MCOB 11.6 responsible-lending rules still require every UK mortgage lender to run an individualised affordability assessment: verified income, committed expenditure, essential and quality-of-living costs, and the effect of at least a 1-percentage-point interest-rate rise over five years. A firm may set an income-multiple or DTI-style limit, but MCOB is explicit that it cannot rely on that limit alone as proof the loan is affordable.