What debt-to-income really measures
Your debt-to-income ratio is the share of your gross monthly income that goes to debt payments. Lenders lean on it more than almost any other number when deciding whether to approve a mortgage, because it’s the cleanest signal of whether you can carry a new payment. The trick most calculators miss: there isn’t one DTI, there are two.
The two ratios
Front-end = housing ÷ income · Back-end = all debt ÷ income
The 28/36 rule says keep the front-end at or under 28% and the back-end at or under 36%. The 43% back-end figure is the Qualified-Mortgage ceiling many lenders treat as a soft cap.
What makes this calculator different
- Both ratios, side by side. Most DTI tools show one number. We split housing from total debt so you see the front-end (28%) and back-end (36%/43%) ratios the way an underwriter does.
- Your lender qualification band. We name where you land — healthy, manageable, caution, or high-risk — against the 36%, 43%, and 50% thresholds, including the 43% Qualified-Mortgage limit.
- Dollar headroom, not just a percentage. We tell you how much more monthly debt you could take on before crossing 36% and 43% — the actionable number basic calculators never give you.
- Editable debt rows. Add every obligation, flag each as housing or other, and watch the ratios and your band update live.
Frequently asked questions
What’s the difference between front-end and back-end DTI?+
Your front-end DTI is your housing payment alone — rent or mortgage PITI — divided by gross monthly income. Your back-end DTI adds in every other monthly debt: car loans, student loans, credit-card minimums, and so on. Lenders look at both, but the back-end ratio is the one that usually decides whether you qualify, because it captures your full debt load. This calculator shows both side by side.
What is the 28/36 rule?+
The 28/36 rule is a long-standing lending guideline: keep your housing costs at or below 28% of gross monthly income (the front-end ratio) and your total debt at or below 36% (the back-end ratio). Staying under both is the comfortable zone — it signals to lenders that you can absorb your payments with room to spare. We compute your 28% housing budget and your 36% headroom in dollars so you can see exactly where you land.
What is the 43% Qualified Mortgage limit?+
Under the Qualified Mortgage (QM) rules that followed the 2008 housing crisis, 43% back-end DTI became a widely used ceiling for loans that get the strongest legal protections for lenders. Many conventional loans still treat 43% as a soft cap, though automated underwriting and compensating factors (a big down payment, strong reserves, high credit score) can push approvals higher. This calculator tells you the dollar headroom you have before crossing 43%.
How can I lower my DTI?+
Two levers move your DTI: less debt or more income. Paying down or paying off a loan removes its monthly payment from the numerator immediately — targeting the debt with the highest payment relative to its balance frees up the most ratio. Avoid taking on new monthly obligations before applying for a mortgage. Raising documented gross income — a raise, a second job, or counting a co-borrower’s income — lowers the ratio from the other side.
Does my DTI affect my credit score?+
No — DTI is not a factor in your credit score. Credit scores use your credit-utilization ratio (balances vs. limits on revolving accounts), not your income, which isn’t even reported to the credit bureaus. DTI is a separate underwriting metric lenders calculate from your application. The two can move together, though: paying down a balance lowers both your utilization and your DTI.
Disclaimer: This calculator is for educational purposes only. Lenders calculate DTI in slightly different ways, count income and debts by their own rules, and weigh compensating factors that can change an approval. It is not financial or lending advice.