Debt-to-Income Ratio Calculator

Background.

Before a mortgage lender looks at the house, it looks at your monthly bills. The question is how much of each pre-tax dollar you earn is already promised to creditors, and the answer comes as two percentages. The front-end ratio counts housing alone: the mortgage payment with property tax, homeowners insurance, mortgage insurance and any HOA dues folded in, or your rent. The back-end ratio adds every other payment a creditor or a court can demand on a schedule — car loans and leases, student loans, credit card minimums, personal loans, child support — and divides the total by the same gross monthly income.

The back-end figure is the one with limits attached. Fannie Mae caps it at 36% for a manually underwritten conventional loan, or 45% when the borrower's credit score and cash reserves meet its eligibility matrix, and its automated system, Desktop Underwriter, will approve nothing above 50%. FHA's manual baseline is 31% for housing and 43% overall. VA lenders use 41% as a guideline but lean on a residual-income test, so a veteran with plenty left over each month can be approved above it. USDA rural loans use 29% and 41% as their standard ratios.

The most quoted number of all, 43%, has a more complicated history. It was the hard cap in the CFPB's 2014 definition of a General Qualified Mortgage, the class of loan that gives lenders legal protection under the federal ability-to-repay rule. A revision finalized in December 2020 swapped that cap for a test based on the loan's price, mandatory from October 2022. Lenders must still weigh DTI or residual income, and some still stop at 43% by choice, but it is no longer the federal line it once was.

Run the numbers at the payment you expect to take on, not just today's rent. A back-end ratio under 36% sits inside every program's total-debt limit; past 45%, approval depends on automated underwriting or on compensating factors such as strong credit and savings.

What is debt-to-income ratio calculator?

Debt-to-income ratio is recurring monthly debt payments divided by gross monthly income, written as a percentage. The front-end, or housing, ratio puts only the housing payment on top of the fraction; the back-end, or total, ratio puts housing plus every other required debt payment there. What counts as debt is much narrower than what counts as spending. Groceries, utilities, phone plans, car insurance, health premiums, income tax and retirement contributions are real costs, yet none of them enter the ratio, and income is measured before tax and payroll deductions. That is why the same household can look comfortable on paper and stretched on a bank statement. VA's residual-income test approaches the question from the other side, counting the dollars left after debts, taxes and living costs instead of a share of pay.

How to use this calculator.

1. 01Gross monthly income: start from pay before tax and deductions. A $78,000 salary is $6,500 a month; $30 an hour for 40 hours a week averages $5,200 (52 weeks spread over 12 months). Self-employment income is usually averaged over recent tax returns, and bonus, overtime or commission counts only with a track record, typically two years.
2. 02Housing payment: if you are buying, enter the full payment on the home you are pricing — principal and interest, a twelfth of the annual property tax and homeowners insurance, mortgage insurance if the loan carries it, and HOA dues. Enter your current rent only to see where you stand today.
3. 03Car loans: add every auto loan and lease payment together. Include a lease even if it ends in a few months.
4. 04Student loans: use the payment on your servicer's statement. If the loans are deferred or show a $0 payment, enter the figure a lender would substitute — 1% or 0.5% of the balance a month, depending on the program — to see what an underwriter will see.
5. 05Credit cards and other debts: enter the minimum due printed on each card statement, not what you actually pay. Put personal loans, child support or alimony you pay, and any other fixed repayment schedule under other debts; leave out utilities, insurance, subscriptions and living costs.
6. 06Read the back-end ratio first, then the category and the front-end ratio. If you are over the limit for the loan you want, multiply the excess in percentage points by your monthly income divided by 100: that is how many dollars of monthly payment have to go.

The formula.

Total monthly debt is D = housing + car + student loans + card minimums + other debts. The back-end ratio is D ÷ I × 100, where I is gross monthly income; the front-end ratio is housing ÷ I × 100; available cashflow is I − D, in dollars.

Because income sits in the denominator, each percentage point is worth the same number of dollars: I ÷ 100, or $60 of monthly payment at $6,000 a month and $100 at $10,000. That makes the calculation easy to run backwards. The largest housing payment a target ratio allows is target × I ÷ 100 minus your other debts, which is how loan officers turn a DTI limit into a price range.

The category is a band on the unrounded back-end ratio: 0 (excellent) below 20%, 1 (good) from 20% up to and including 35%, 2 (concerning) above 35% through 49%, and 3 (critical) above 49%. These bands are a summary set around the published lines — Fannie Mae's 36% manual limit, FHA's 43% baseline and the former QM cap, DU's 50% ceiling — rather than any one lender's rule, and a ratio a few hundredths above 35% or 49% falls into the higher band even though it displays as the round number.

Two simplifications matter. The arithmetic takes your entries at face value, so program rules such as substituting a share of a deferred student-loan balance are applied only if you enter the substituted payment yourself. And available cashflow is pre-tax: income tax, payroll deductions and every living cost still come out of it.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Consumer Financial Protection Bureau — Ability-to-Repay and Qualified Mortgage Rule, 12 CFR §1026.43 (Regulation Z). Establishes the General QM 43% back-end DTI threshold and ability-to-repay safe harbor for residential mortgages.
2. [2]Fannie Mae Selling Guide, Section B3-6-02 — Debt-to-Income Ratios. Defines conventional 36% manual underwriting maximum and up to 45%/50% via Desktop Underwriter with compensating factors.
3. [3]FHA Single Family Housing Policy Handbook 4000.1, Part II.A.5.b — Qualifying Ratios. Establishes the 31% front-end / 43% back-end manual underwriting standard and the 50% ceiling reachable through the TOTAL Scorecard with compensating factors.
4. [4]Federal Reserve — G.19 Consumer Credit statistical release. Monthly time series of household consumer debt outstanding and effective interest rates by credit category.
5. [5]Federal Reserve Bank of New York — Quarterly Household Debt and Credit Report. Tracks aggregate household leverage, debt composition, and delinquency rates — the empirical basis for DTI-based risk modelling.
6. [6]Brookings Institution — Household leverage and the recession of 2007–09 (Mian & Sufi, Brookings Papers on Economic Activity). Peer-reviewed analysis of household debt-to-income ratios as a driver of mortgage default and consumption collapse.
7. [7]Consumer Financial Protection Bureau — What is a debt-to-income ratio? (Ask CFPB consumer guidance).