What is a debt-to-income ratio?

Debt-to-income (DTI) is the share of your gross monthly income that goes to debt payments. It is the single number lenders use most to judge affordability: lower is safer. The back-end ratio counts all debt; the front-end ratio counts only housing costs.

How is DTI calculated?

DTI = total monthly debt payments ÷ gross monthly income × 100. For example, 1,800 in monthly debt against 5,000 of gross income is 1,800 ÷ 5,000 = 0.36 = 36%. The front-end ratio uses only your housing payment in the numerator.

What is the difference between front-end and back-end DTI?

The front-end (housing) ratio is just your rent or mortgage divided by income — lenders often want this under 28%. The back-end ratio adds in every other debt (cars, cards, student loans) and is the headline figure underwriters care about most, usually capped around 36% to 43%.

What is a good debt-to-income ratio?

Under 36% is widely considered healthy and keeps the best products open to you. Up to 43% is still approvable for many mortgages but invites closer scrutiny. Above 43% you are stretched, and above 50% most prime lenders will decline.

Should I use gross or net income for DTI?

Lenders use gross income — your pay before tax and deductions — so this calculator does too. Using net income would understate the ratio relative to how a lender sees it, so always enter the pre-tax figure for a like-for-like result.

Does this calculator store or send my financial data?

No. Every figure is calculated in your browser and a copy is saved only in this browser's local storage so your numbers are still here next time. Nothing is ever uploaded to a server.

Debt-to-Income Ratio Calculator

A debt-to-income (DTI) ratio calculator that turns your monthly debt payments and income into the exact percentages a lender uses to decide how much you can borrow. It reports both your back-end DTI (every debt) and your front-end DTI (housing only), places you in a clear lender band, and shows your residual income and how much headroom you have before the classic 36% comfort line. It is for anyone sizing up a mortgage, remortgage, car loan or balance-transfer — or simply checking whether their finances are carrying too much debt.

How it works

Lenders rarely look at the size of a debt in isolation; they look at it relative to what you earn. That relationship is the debt-to-income ratio. This tool computes two versions of it. The back-end ratio divides the sum of all your monthly debt payments by your gross monthly income. The front-end ratio divides only your housing payment — rent or mortgage — by the same income. Tick the “Housing” box on a debt line and it counts toward the front-end figure as well as the total.

Once it has both ratios, the calculator maps your back-end DTI onto the underwriting bands most mortgage and consumer lenders use: comfortably under 36% is healthy, up to 43% is the upper edge of many “qualified mortgage” rules, and beyond that you move into stretched and high-risk territory. It also works out your residual income — what is left each month after debt — and the headroom you still have before hitting the 36% line, expressed as a monthly amount of new debt you could take on. A doughnut chart breaks your income into housing debt, other debt and the share left free, so you can see the whole picture at a glance.

Worked example

Suppose your household earns a gross 5,000 per month. Your debts are a 1,400 mortgage (housing), a 300 car loan, 200 in credit-card minimums and a 150 student loan — 2,050 in total.

Back-end DTI = 2,050 ÷ 5,000 = 41.0% — inside the 43% ceiling but in the “stretched” approach zone, so a strong deposit or credit score would help.
Front-end DTI = 1,400 ÷ 5,000 = 28.0% — right on the housing guideline.
Residual income after debt = 5,000 − 2,050 = 2,950 per month.
Headroom to the 36% line = 5,000 × 0.36 − 2,050 = −250, meaning you are 250/month of debt over the comfort line and would need to trim payments to get back under it.

Clear the 200 of card minimums and your back-end DTI drops to 37.0%, almost back inside the comfort band — a concrete illustration of why paying down small revolving balances moves the needle fastest.

Formula note

Back-end DTI = (sum of all monthly debt payments ÷ gross monthly income) × 100. Front-end DTI = (monthly housing payment ÷ gross monthly income) × 100. Residual income = gross monthly income − total monthly debt. The 36% headroom figure is income × 0.36 − total debt. All inputs are user-entered; the tool uses no external rates and makes no network calls. Currency is just a display symbol — change it freely to match wherever you are.