What your debt-to-income ratio tells a lender
Your debt-to-income ratio (DTI) is the share of your gross monthly income that already goes to debt payments. It is one of the first numbers a mortgage lender looks at, because it shows how much room you have to take on a new payment. A low DTI means a lender can lend more with less risk; a high DTI means even a small new loan could stretch your budget.
Mortgage lenders look at two versions:
- Front-end DTI (the housing ratio): only your housing payment.
- Back-end DTI (the total ratio): housing plus every other monthly debt payment.
When people say “DTI” without a qualifier, they usually mean the back-end ratio.
The DTI formula
Back-end DTI = (housing payment + other monthly debt payments) ÷ gross monthly income × 100
Housing payment is your rent, or, when you are applying for a mortgage, the full new payment: principal, interest, property tax, home insurance, mortgage insurance and HOA dues.
Gross monthly income is income before tax: salary or wages, plus regular bonuses, self-employment income, rental income, pensions and alimony or child support received. If your salary is $84,000 a year, your gross monthly income is $7,000.
What counts as debt (and what does not)
| Counted in DTI | Not counted |
|---|---|
| Mortgage or rent payment | Utilities (power, water, internet) |
| Car loans and leases | Phone and streaming subscriptions |
| Student loans (the required payment) | Car, health and life insurance |
| Credit card minimum payments | Groceries, fuel, childcare |
| Personal loans, buy-now-pay-later plans | Income tax and payroll deductions |
| Child support and alimony you pay | Medical bills not in a payment plan |
For credit cards, lenders use the minimum payment on your statement, not your balance or what you actually pay. For student loans in deferment, lenders follow program rules that may use a percentage of the balance, so ask your lender.
Worked example 1: the default numbers
Someone earns $84,000 a year ($7,000 a month). Rent is $1,900, and they pay $450 on a car loan, $300 on student loans and $120 in card minimums.
- Front-end DTI = $1,900 ÷ $7,000 = 27.1%
- Other debts = $450 + $300 + $120 = $870
- Back-end DTI = ($1,900 + $870) ÷ $7,000 = $2,770 ÷ $7,000 = 39.6%
The housing ratio is under the 28% conventional guideline, but the total is above 36%. Most conventional lenders would still consider them with good credit, FHA’s 43% guideline is met, and there is $240 a month of room under 43%.
Worked example 2: checking a mortgage before you apply
A couple earns $6,000 a month and is looking at a home with a full payment of $1,800. They have a $350 car payment and a $250 card minimum.
- Front-end = $1,800 ÷ $6,000 = 30%
- Back-end = ($1,800 + $600) ÷ $6,000 = 40%
That fails the 28/36 conventional guideline but fits FHA’s 31/43. If they pay off the card first, the back-end ratio falls to $2,150 ÷ $6,000 = 35.8%, under 36%. Clearing one small balance before applying can change which loans you qualify for, and sometimes the rate.
Worked example 3: the income you need
The calculator also shows the income that would bring your ratio down to a target. In example 1, total debts are $2,770 a month:
- For 43%: $2,770 ÷ 0.43 = $6,442 a month ($77,302 a year)
- For 36%: $2,770 ÷ 0.36 = $7,694 a month ($92,333 a year)
So the same debts that look “manageable” on $84,000 would look “healthy” on about $92,000.
DTI limits by loan type
| Loan type | Front-end | Back-end | Notes |
|---|---|---|---|
| Conventional, manual underwriting | 28% (guideline) | 36% | Fannie Mae’s manual limit |
| Conventional, strong credit and reserves | — | 45% | Fannie Mae, with credit score and reserve requirements |
| Conventional, automated (Desktop Underwriter) | — | 50% | Maximum Fannie Mae allows |
| FHA | 31% | 43% | Higher with compensating factors |
| VA | — | 41% | Plus a residual income test |
| USDA | 29% | 41% | Guaranteed rural housing loans |
You may also see 43% described as the limit for a “Qualified Mortgage.” That was the CFPB’s original General QM test; the current rule uses price-based limits instead, but many lenders still treat 43% as a practical ceiling.
How the bands in this calculator work
| Back-end DTI | Label | What it usually means |
|---|---|---|
| 36% or less | Healthy | Meets most guidelines; best chance of good terms |
| 36.01% to 43% | Manageable | Approvable for many loans, less room for new debt |
| 43.01% to 50% | High | Needs automated approval or strong compensating factors |
| Over 50% | Very high | Most mortgage programs will decline |
These bands are a guide, not an approval. Lenders also weigh your credit score, savings, job history and the property.
DTI is not the same as credit utilization
Your credit score does not use DTI at all, because credit bureaus do not know your income. Instead, scores look at credit utilization: your card balances divided by your card limits. You can have a low DTI and a poor utilization (big balances, small minimums), or the reverse. Lenders check both, so paying down card balances helps twice: it lowers your minimum payments and your utilization.
Tips to improve your DTI
- Target high-payment, low-balance debts. A $1,500 card balance with a $60 minimum and a $3,000 car loan with $400 left a month affect DTI very differently. Paying off the last few months of a car loan can drop DTI by several points.
- Do not open new credit before applying. A new car loan or store card raises your DTI and can lower your score at the worst moment.
- Add all eligible income. Steady bonus, overtime, part-time or rental income can count if it is documented, usually over two years.
- Consider a co-borrower. Their income and debts are combined with yours.
- Shop for a smaller payment. A lower price, a larger down payment or a lower rate all shrink the housing payment. The house affordability calculator shows the price your ratios allow.
Common mistakes
- Using take-home pay. DTI uses gross income. Using net pay makes your ratio look worse than lenders will see it. To check what you actually take home, use the paycheck calculator.
- Using today’s rent in a mortgage check. When you apply for a mortgage, the new payment replaces your rent. Use the full estimated payment from the mortgage calculator.
- Forgetting tax and insurance. The housing payment includes property tax, insurance, mortgage insurance and HOA, not just principal and interest.
- Counting paid-in-full cards. If you pay your card in full and the statement shows no minimum due, lenders may count a small payment or none at all.
If you are comparing loan programs, the FHA loan calculator and VA loan calculator show the full payment to plug in as your housing cost.