More mortgage applications die on two percentages than on any other line of the file. Your credit score gets the attention, your down payment gets the saving plan, but the number a lender's underwriting engine checks first is your debt-to-income ratio — your DTI. It answers the only question the lender truly cares about: after your existing debts take their monthly cut, is there honestly room left for this new housing payment? This calculator produces the two versions of that number every lender computes — the front-end ratio and the back-end ratio — and places them next to the guidelines conventional, FHA, and VA programs actually use, so you can see your application the way an underwriter will.

The two ratios, defined precisely.

The front-end ratio, sometimes called the housing ratio, is your monthly housing payment divided by your gross monthly income, expressed as a percentage. Housing payment means the full payment, not just principal and interest: principal, interest, property taxes, homeowners insurance, and HOA dues if you have them — plus mortgage insurance where it applies. The back-end ratio, sometimes called the total obligations ratio, takes that same housing payment and adds every other recurring monthly debt on your credit report: car payments, credit card minimum payments, student loan payments, personal loans, and similar obligations. That total is then divided by the same gross monthly income. Two details surprise people every time. First, income is gross — before taxes and deductions — because the lender is measuring the total flow your debts compete against. Second, for credit cards the lender uses the minimum payment shown on your report, not your balance and not what you actually pay. A $6,000 card balance with a $95 minimum counts as $95 a month of debt, whether you plan to pay it off next week or not.

A worked example, dollar by dollar.

Here is the full math for this calculator's standard case. Gross monthly income: $7,500 — that is a $90,000 salary divided by twelve. Housing payment: $1,850. Car payment: $420. Credit card minimums: $95. Student loan payment: $210. Other debts: zero. The front-end ratio is $1,850 divided by $7,500, which is 24.67 percent. Non-housing debts total $420 plus $95 plus $210, which is $725. Total monthly debts are $1,850 plus $725, which is $2,575, and the back-end ratio is $2,575 divided by $7,500, which is 34.33 percent. Now read those two numbers the way a lender does. The classic housing guide is 28 percent, and this borrower's 24.67 percent sits comfortably under it — at this income, the 28 percent guide would allow a housing payment of $2,100, some $250 above the actual payment. The total debts of $2,575 sit $800 below the $3,375 that a 45 percent back-end benchmark allows on this income. Verdict: an easy approval on ratios alone, under every program discussed on this page. That is what a clean DTI profile looks like, and it is worth knowing your own two numbers before a lender tells you.

What counts as a debt — and what does not.

The back-end ratio is built from debts that appear as recurring obligations, and the boundary lines matter. Counted: auto loans and leases, student loans, credit card and charge card minimums, personal loans, installment loans of every flavor, child support and alimony obligations, and any co-signed loan where you are legally on the hook — yes, the car you co-signed for your brother counts against you even if he has never missed a payment, because the obligation is legally yours. Not counted: utilities, groceries, gas, streaming subscriptions, gym memberships, health insurance premiums, and income taxes. Those costs are real, and they absolutely affect whether you can afford a home, but the ratio ignores them, which is one reason a lender's approval is not the same thing as a personal budget blessing. Two special cases deserve attention. Student loans in income-driven repayment are handled differently by different programs: where the documented payment is very low or zero, some programs substitute a percentage of the outstanding balance as the assumed payment, which can raise a borrower's DTI sharply on paper — if that is your situation, ask your lender which figure each program will use before you apply. And installment debts close to payoff get a break in some programs: conventional guidelines let lenders exclude a non-mortgage installment debt with only a handful of payments remaining — commonly framed as ten months or fewer — because the obligation is about to vanish.

Conventional loans: the 28/36 legacy and the modern reality.

The textbook conventional guideline is the old 28/36 rule: housing at or under 28 percent of gross income, total debts at or under 36 percent. It is still taught, still printed, and worth respecting as a personal comfort line — a household at 28/36 has genuine breathing room. But it is a guide, not the law of modern underwriting. In practice, many conventional lenders work to a back-end benchmark near 45 percent, and automated underwriting systems — the software that issues most approvals — sometimes approve higher ratios still for borrowers with strong credit, large cash reserves, or a small payment increase from their current housing cost. The honest way to use this calculator is therefore layered: treat 36 percent back-end as your green zone where almost any lender says yes, the stretch between there and about 45 percent as the normal working range where your overall file decides, and anything above 45 percent as territory that needs either a government-backed program, compensating strengths, or debt reduction before you apply. Lender overlays — individual lenders' stricter in-house caps — sit on top of all of this, which is why one bank's no is sometimes another bank's yes at the identical DTI.

FHA: higher ceilings, earned with compensating factors.

FHA underwriting is built for borrowers whose ratios run hotter, and its published benchmarks say so. Through FHA's automated TOTAL scorecard, front-end ratios up to about 46.9 percent and back-end ratios up to about 56.9 percent can be approved when the file carries compensating factors — strengths that offset the ratio. Recognized compensating factors include verified cash reserves after closing, a minimal increase over your current housing payment (you are already proving you can carry nearly this much), additional documented income that was not used to qualify, and a history of handling payments at this level. Read the structure of that correctly: the high ceilings are not an entitlement for every FHA borrower; they are headroom the system grants when the rest of the file argues you can carry it. Manually underwritten FHA files are stricter than the automated ceilings. For the borrower on this page's standard example, none of this matters — at 24.67 and 34.33 percent, FHA ratios are a formality. It matters enormously for the stretched borrower in the next section, for whom FHA's ceiling room is frequently the entire ballgame.

VA: the program that broke the ratio mold.

VA loans take a genuinely different approach. There is no front-end ratio test at all, and the back-end ratio carries a guideline benchmark of 41 percent rather than a hard cap. Above 41 percent, a VA loan is not automatically dead — but the lender must look closely at the program's second test, residual income: the money left over each month after all debts, taxes, and estimated maintenance and utilities, measured against regional and family-size tables. A veteran at 48 percent back-end with strong residual income can be approved; a veteran at 39 percent with almost nothing left over can fail. This is, frankly, the most honest underwriting on the page, because it asks whether money actually remains after the bills — the question the borrower's own budget asks every month. If you are VA-eligible and your back-end ratio worries you, run it, then ask a VA lender to run your residual income too; the second number may rescue the first.

A stretched file, and how it gets fixed.

Now the opposite profile. A renter earning $4,800 a month gross wants to buy. Rent is $1,600 — close to the target mortgage payment, so use $1,600 as the housing figure. Car payment $450, card minimums $180, student loan $260. Front-end: $1,600 over $4,800 is 33.33 percent, above the classic 28 guide. Back-end: total debts of $2,490 over $4,800 is 51.88 percent. Conventional approval at that ratio is a long shot. FHA's automated ceilings could reach it with real compensating factors, but it is far smarter to repair the ratio before applying, and the repair math is encouragingly mechanical. Every $100 of monthly debt removed on a $4,800 income cuts the back-end ratio by just over two percentage points. Eliminating the $180 in card minimums — by paying those balances down to zero, not by closing the cards — drops the back-end ratio to 48.12 percent. Paying off a nearly-finished car loan or choosing a target home $150 a month cheaper moves it further. Note what does not work: paying $2,000 extra toward a car loan whose payment stays $450 changes the ratio not at all, because DTI counts payments, not balances. The fastest DTI repair always targets the payment that disappears entirely for the least cash — usually a small-balance card or a loan with a few payments left.

Lowering your DTI: the full playbook.

Work the levers in order of cash efficiency. First, kill small payments outright: list every debt by the cash needed to make its payment vanish, smallest first, and retire those — each extinguished payment is worth far more to your ratio than the same dollars spread across balances. Second, do not take on new debt in the months before applying: a fresh car loan is the single most common self-inflicted DTI wound in mortgage lending. Third, use the near-payoff rule where it exists — if a debt has only a few payments left, some programs exclude it, and finishing it early guarantees the exclusion. Fourth, reconsider the target: a slightly cheaper home lowers the housing leg of both ratios at once. Fifth, the income leg: a co-borrower's documented income counts fully, and documented, stable additional income — a longstanding second job, for instance — can be included where program rules allow; a hoped-for raise cannot. Finally, give it time when time is what the file needs: debts amortize every month whether you strategize or not, and six months of ordinary payments plus one extinguished card has rescued many files that looked hopeless in spring.

DTI beyond mortgages.

The same back-end ratio quietly gates much of your financial life. Landlords commonly approve renters whose housing cost fits near a third of gross income, and many screen total obligations too. Auto lenders and personal-loan underwriters run their own versions of the back-end test, which is why a borrower can be approved for a mortgage and declined for a small personal loan in the same month — the new loan application arrives with the mortgage already inside the ratio. Credit card issuers ask for income and housing payment for exactly this computation. And none of these institutional tests replaces the personal one: a 34 percent back-end ratio at $7,500 a month leaves a very different life than 34 percent at $3,000 a month, because food, fuel, and childcare do not scale with income. Use this calculator to pass the lender's test; use your own budget to pass yours.

How to use this calculator well.

Enter gross monthly income — salary divided by twelve, before tax, using only income you can document. Enter the housing payment the way a lender builds it: for a purchase, principal, interest, taxes, insurance, HOA, and mortgage insurance combined; our house affordability calculator can assemble that figure for a target price. List debts by their monthly payments exactly as they appear on your credit report, card minimums included, and put anything else recurring — a personal loan, a support obligation — in the other debts field. Then read the results in this order: back-end ratio first, because it is the number most likely to decide your file; front-end second; and the room left under the 45 percent benchmark last, because that dollar figure is your shopping guide — it tells you exactly how much monthly debt you must shed, or how much cheaper a home you must choose, to walk into the normal approval range. Run it again after every debt you pay off. DTI is the rare financial number that improves the moment you act on it, in writing, before you ever speak to a lender.

With the pre-filled defaults — Gross Monthly Income (before tax) $7,500, Monthly Housing Payment (rent or PITI + HOA) $1,850, Monthly Car Payment $420, Credit Card Minimum Payments (total) $95, Monthly Student Loan Payment $210, Other Monthly Debt Payments $0 — the Debt-to-Income Calculator returns Non-Housing Debts (monthly) $725.00, Total Monthly Debts $2,575.00, Front-End Ratio (housing only) 24.67%, Back-End Ratio (all debts) 34.33%, Housing Budget at 28% Guide $2,100.00, Max Total Debts at 45% Benchmark $3,375.00, Debt Room Left Under 45% $800.00. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.