Debt-to-Income (DTI) Ratio Calculator

How the debt-to-income ratio is calculated

Your debt-to-income ratio (DTI) is the share of your gross monthly income that goes to debt payments. This DTI calculator gives you both versions lenders use. The front-end ratio counts only housing: rent, or for a mortgage the full payment including principal, interest, property taxes, insurance and HOA dues. The back-end ratio adds every other recurring debt: car loans, student loans, credit card minimum payments, personal loans, and child support or alimony you pay. When a lender or article says "DTI" without qualifying it, they mean the back-end number.

Income is gross, before taxes and deductions, and only income a lender can document counts: salary, regular overtime and bonuses with a history, self-employment income averaged over two years, child support you receive, Social Security and pensions. Utilities, groceries, phone bills, insurance premiums and 401(k) contributions are not debts and do not go in the ratio.

Worked example

Someone earning $72,000 a year has a gross monthly income of $6,000. Rent is $1,500, a car payment $400, student loans $250 and credit card minimums $100. Front-end DTI = 1,500 ÷ 6,000 = 25%. Total debts are $2,250, so back-end DTI = 2,250 ÷ 6,000 = 37.5%. That lands in the yellow zone: fine for most loans, but there is no room to add a payment and stay under 36%. To get to 36% on the same debts you would need $6,250 a month ($75,000 a year), or $90 less in monthly payments.

What DTI do lenders accept?

The classic rule of thumb is 28/36: housing under 28% of income, all debt under 36%. In practice the limits are looser. Conventional loans run through Fannie Mae and Freddie Mac automated underwriting typically allow up to 45%, and up to 50% for borrowers with strong credit scores and cash reserves. FHA loans use 31/43 as the baseline and routinely approve higher ratios with compensating factors. VA loans use 41% as a guideline but lean more on residual income, and USDA loans use 29/41. Credit cards and auto lenders rarely publish a limit, but a back-end ratio above 43% to 50% is where approvals and rates start to suffer across the board.

Common mistakes

• Using take-home pay. DTI is based on gross income. Using net pay overstates your ratio by a quarter or more.
• Entering card balances instead of minimums. Lenders use the minimum payment from your credit report, usually 1–3% of the balance.
• Forgetting the new mortgage. When you apply for a home loan, the lender replaces your current rent with the proposed mortgage payment. Enter the payment you are applying for, not what you pay now.
• Ignoring deferred student loans. Even with $0 due today, mortgage lenders typically count 0.5% to 1% of the balance as a monthly payment.

When the ratio is misleading

DTI says nothing about your credit score, savings or the size of your down payment, and those often matter more at the margin. Two people with a 40% DTI can get very different answers if one has a 780 score and six months of reserves and the other has a 640 score and none. It also ignores taxes: a 36% DTI on $200,000 leaves far more spending money than 36% on $40,000. Use the ratio to understand how a lender will see you, then look at your actual monthly budget to decide what you can comfortably afford.