Comprehensive Guide
Learn more in our Personal Finance Guide.
How it works
Your debt-to-income ratio (DTI) is what lenders use to decide if you can handle additional debt. It equals total monthly debt payments divided by gross monthly income, expressed as a percentage. There are two types: front-end DTI (housing costs only, should be below 28%) and back-end DTI (all debt, should be below 36%). Lenders want back-end DTI below 43% for conventional mortgages, though FHA allows up to 50% with compensating factors. A high DTI is the number-one reason mortgage applications get denied. The calculator sums all your monthly debt obligations, divides by gross income, and compares against lender thresholds. It also shows the maximum housing payment you can afford under the 28% front-end rule. Every field in this calculator exists for a reason. Enter Gross monthly income, Monthly mortgage / rent, Monthly car payment, Monthly student loan, Monthly credit card payment, and the engine recomputes the results instantly — no signup, no email, and nothing is sent to a server, because the math runs entirely in your browser. Change one input at a time to see which lever moves the result most; that sensitivity, not any single number, is usually the real insight. The worked example below the form uses realistic defaults so you can sanity-check the output before trusting it with your own figures, and the formula is published on the page so you can verify every step of the arithmetic yourself.Formula
DTI = (Total monthly debt ÷ Gross monthly income) × 100
Tips
- Below 20% is excellent. Below 36% gets the best mortgage rates.
- Above 43% makes conventional mortgage qualification difficult.
- Pay off one small debt entirely to get a quick DTI improvement.
- Do not take on new debt before applying for a mortgage.
Frequently asked questions
What DTI do I need for a mortgage?
Conventional loans require DTI below 43%, ideally below 36%. FHA allows up to 50% with compensating factors. VA loans prefer below 41%.
How do I lower my DTI?
Pay down debt (especially high-balance accounts), increase income, or both. Avoid taking on new debt before applying for a mortgage.
How accurate are the calculator results?
The math is exact — the same formulas a financial professional would use by hand. The precision of the output depends entirely on how realistic your inputs are. Use your actual numbers rather than estimates when possible. The defaults are reasonable starting points, but your real income, rates, and timeline will produce a different result.