Compute your front-end and back-end DTI ratios, the metrics lenders use to qualify you.
Back-end DTI
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Front-end DTI (housing)
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Available room (back-end to 43%)
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Two ratios, and why lenders care about the second one most
Debt-to-income is the single number a mortgage underwriter trusts more than almost anything else on your application, because it answers a blunt question: after your obligations, can you still make the payment? This calculator returns two versions. The front-end ratio is your housing payment divided by gross monthly income. The back-end ratio adds every other required monthly debt to the housing number, then divides by the same income. Both use gross income, the figure before taxes and 401(k) deferrals, which surprises people who budget on take-home pay.
Whose tool is this? Anyone within a year of applying for a mortgage, refinancing, or taking on a large installment loan. The classic benchmark is the 28/36 rule: keep housing at or below 28 percent and total debt at or below 36 percent of gross income. Government-backed loans stretch further. FHA routinely approves back-end ratios into the 43 to 50 percent range when other factors are strong, and the Consumer Financial Protection Bureau treats 43 percent as a meaningful line for qualified mortgages.
Running a $9,000-a-month household
Take someone earning $9,000 gross per month with a $2,200 housing payment and $600 in other monthly debt, say a car loan and a student loan minimum. Front-end DTI is 2,200 divided by 9,000, which is 24.4 percent, comfortably under 28. Back-end DTI is 2,800 over 9,000, or 31.1 percent, which sits in the excellent conventional range below 36. The calculator also shows headroom to the 43 percent threshold: 0.43 times 9,000 is 3,870, minus the 2,800 already committed, leaving $1,070 a month of additional debt capacity before underwriting tightens.
| Step | Figure |
|---|---|
| Gross monthly income | $9,000 |
| Housing payment (PITI) | $2,200 |
| Other monthly debt | $600 |
| Front-end DTI | 24.4% |
| Back-end DTI | 31.1% |
| Room to 43% back-end | $1,070 per month |
What underwriters count, and the trap people fall into
The back-end ratio includes minimum required payments on mortgages, auto loans, student loans, credit cards, personal loans, and court-ordered support. It does not include utilities, groceries, gas, phone bills, or insurance you pay directly. The common mistake is the opposite extreme: leaving out a debt that counts. Student loans in deferment still get a payment imputed by most programs, and a co-signed loan you never use shows up on your credit report as your obligation. A car you plan to pay off next month still counts today unless you can document the payoff.
The fastest way to lower a borderline ratio
A practical tip if you are close to a threshold: paying down a revolving balance moves the needle faster than people expect, because the minimum payment, not the balance, is what enters the ratio. Knocking out a $400-a-month car loan can do more for your approval odds than a $10,000 raise that lands after taxes. Lenders also let you pay a loan down to within ten months of payoff and exclude it entirely on conventional files, so retiring the last stretch of an auto loan can erase its payment from the math altogether.
Common DTI questions
Does my credit card balance or my minimum payment count?
The minimum monthly payment, not the full balance, is what enters back-end DTI. A $12,000 card balance with a $250 minimum adds $250 to your monthly debt, not $12,000. That said, a high balance hurts your credit utilization and your score separately, so it can still raise your rate even when the DTI math looks fine.
Can I get approved with a DTI above 43 percent?
Sometimes. FHA loans, VA loans, and certain portfolio lenders go higher when you have compensating factors such as a large down payment, significant cash reserves, or a strong credit history. Above roughly 50 percent the options thin out quickly and the pricing gets worse, so treat the 43 percent line as the point to start paying down debt rather than a hard wall.