Debt-to-income calculator

Your DTI is two ratios, not one. This tells you both — the housing-only front-end and the all-debt back-end — and where lenders actually draw the line versus where the math says you should be.

How the math works

DTI is a ratio of monthly debt payments to gross monthly income, expressed as a percentage. Lenders read two versions of it. The front-end ratio counts only your housing payment. The back-end ratio counts every recurring debt.

The housing payment is the full figure — principal, interest, property tax, homeowners insurance, and PMI or HOA dues if you have them — or your rent if you're not yet an owner. Other debt means the minimum monthly payments on car loans, student loans, credit cards, and any other fixed obligation. It leaves out utilities, groceries, insurance premiums, and subscriptions. Those are spending, not debt.

One quirk decides everything downstream: the denominator is gross income, the money before tax. That's the lender's convention, and it's the reason the ratio reads lower than the pinch you actually feel. More on that below.

Worked example

Take a household earning the U.S. median household income of $80,610 — $6,717.50 a month gross. Their housing payment is $1,700 and their other debt (a car loan plus a card minimum) runs $700 a month.

Front-end DTI is $1,700 ÷ $6,717.50, or about 25.3%. Back-end DTI is $2,400 ÷ $6,717.50, or about 35.7%. Both sit under the conventional 28/36 guideline — 28% for housing, 36% for total debt. On paper, this household is in good shape.

Here's where most calculators stop and this one keeps going. A lender running Fannie Mae's automated underwriting will approve a back-end DTI up to 50% with compensating factors. At 50% of $6,717.50, that's $3,358.75 a month in total debt — roughly $940 a month more than the $2,418.30 the 36% guideline allows. The lender will happily approve nearly a thousand dollars a month of debt beyond the prudent line.

When this calculator is wrong

The number this tool gives you is the same number a lender computes. That doesn't make it a verdict on whether you can afford the debt. Four ways the ratio misleads:

• "Approved" is not "affordable." The 28/36 rule is a prudence guideline; it is not the lender's approval line. Fannie Mae's Desktop Underwriter goes to 50% back-end DTI with strong credit and reserves. The old Qualified Mortgage safe harbor drew its line at 43% before the CFPB replaced that hard cap with a price-based test in 2021. The gap between 36% and 50% is the difference between what a lender will sign off on and what leaves you room to breathe.
• It's measured on gross income. A 36% back-end DTI is 36% of pre-tax income. FICA alone takes 7.65% off the top — 6.2% Social Security plus 1.45% Medicare — before a dollar of income tax. Against take-home pay, a debt load that reads as 35.7% on gross is closer to 38.7% of what actually lands in the account. The ratio is designed to look smaller than the squeeze.
• It's blind to the rate and size of the debt. Two households at an identical 36% DTI aren't in the same position if one carries a 6.85% mortgage and the other carries the U.S. average credit card APR of 22.76%. DTI counts the payment, not the interest behind it.
• It's a snapshot. The ratio is true the day you compute it. A promotional 0% card, a deferred student loan, or an interest-only period can hide a payment that jumps later. The DTI moves the moment the payment resets.

What to do with the result

If your back-end DTI is under 36%, you're inside the conventional guideline and a mortgage underwriter will treat the ratio as a non-issue. The useful move is to stop optimizing the ratio and look at the interest rates behind the payments instead.

If you're between 36% and 43%, you're still approvable but past the prudent line. Bringing the ratio down means either raising the denominator (more gross income) or shrinking the numerator (less debt), and the numerator is the faster lever — a car loan paid off or a card balance cleared drops the ratio immediately. Use the mode toggle above to see how much total debt fits under a target you set.

If you're above 43%, a conventional loan gets hard, and the number to watch is the payment, not the balance. The practical next step is to attack the highest-rate debt first, which lowers both the ratio and the interest bleed at the same time.

Common questions

What's a good debt-to-income ratio?

Under 36% back-end is the conventional prudence line, with housing under 28% of that. Lenders will approve higher — up to 50% under automated underwriting with compensating factors — but "will approve" and "is comfortable" are different thresholds. Aim for the guideline, not the ceiling.

Does rent count in my DTI?

Yes. Rent is your current housing payment, so it goes in the front-end and back-end ratios. When you take out a mortgage, the rent is replaced by the new housing payment in the calculation.

Does DTI use gross or net income?

Gross — income before tax. That's the lender's convention, and it's why the ratio reads lower than the actual bite on your paycheck. FICA alone removes 7.65% before any income tax, so the same debt is a larger share of take-home pay than the DTI suggests.

What debts are left out of DTI?

Utilities, groceries, gas, phone and streaming subscriptions, and insurance premiums. DTI counts fixed debt obligations — mortgage or rent, car loans, student loans, and credit card minimums — not general living costs.

Is 43% still the mortgage limit?

Not as a hard cap. The 43% figure was the Qualified Mortgage safe-harbor line until 2021, when the CFPB replaced it with a price-based test. Conventional automated underwriting now approves up to 50% back-end DTI with compensating factors, though the 28/36 guideline remains the prudent target.