Debt-to-Income (DTI) Calculator — Front-End & Back-End Ratio

Your debt-to-income ratio (DTI) is the qualification number a lender checks before approving your mortgage, car loan or personal loan — and it sets how much they'll let you borrow. DTI is a pure cash-flow test: it weighs the debt payments leaving your account each month against your monthly income, expressed as a percentage. It has nothing to do with how much cash you have saved, your down payment, or your closing costs — those are about funds, while DTI is strictly about monthly affordability. (If you're sizing up the cash you'll bring to the table instead, that's a separate question for our Down Payment Calculator.) The lower your DTI, the more room you have to absorb a rough month, and the safer you look to an underwriter.

DTI comes in two flavors, and both use gross monthly income (your pay before taxes and deductions), not take-home pay.

Back-end DTI is the one people mean when they just say "DTI." It's all your monthly debt payments divided by gross monthly income:

Back-end DTI = (total monthly debt ÷ gross monthly income) × 100.

That "total debt" bucket includes your housing payment (rent, or mortgage principal + interest + property tax + insurance), car loans, student loans, minimum credit card payments, and any other loan or alimony/child support. It does not include groceries, utilities, gas, streaming, or your phone bill — those are living expenses, not debt obligations a lender pulls from your credit report.

Front-end DTI (the "housing ratio") is just your housing payment divided by gross income:

Front-end DTI = (monthly housing payment ÷ gross monthly income) × 100.

Worked example. Say you earn $6,000/month gross. Your rent or mortgage is $1,500, car payment $400, student loan $300, and credit card minimums $150. Total debt = $1,500 + $400 + $300 + $150 = $2,350.

Back-end DTI = 2,350 ÷ 6,000 = 39.2%. Front-end DTI = 1,500 ÷ 6,000 = 25.0%.

What the numbers mean. A back-end DTI under 36% is considered healthy and gives you room to qualify with most lenders at the best rates. Conventional loans often cap out around 43%, the classic "qualified mortgage" ceiling, though some programs (FHA, or with strong compensating factors) stretch to 50%. Front-end DTI is usually expected to stay near or below 28%. That's where the well-known 28/36 rule comes from: keep housing ≤ 28% and total debt ≤ 36%. Note that DTI is about qualifying, not about your final payment — to size the actual monthly housing number that feeds the front-end ratio, use our Mortgage Payment Calculator.

The most common mistake: using net (take-home) pay instead of gross income — that inflates your DTI and makes you look worse than lenders actually see you. The second trap is leaving out a debt (a co-signed loan still counts) or, conversely, counting utilities and groceries as "debt." If your back-end ratio is too high to qualify, the fix is to reduce the monthly payments in the numerator — folding several balances into one lower payment can do that, which our Debt Consolidation Calculator estimates. This is an estimate to help you plan — your lender's exact calculation may differ.