The sample DTI calculation below uses round, illustrative numbers to show the math. It is not a quote, an approval, or a prediction of your result, which depends on your income, your debts, the loan program, and underwriting.
What is debt-to-income ratio, and how is it calculated?
Debt-to-income ratio (DTI) is the share of your gross monthly income that goes to your monthly debt payments. As the Consumer Financial Protection Bureau describes it, you add up your required monthly debt payments and divide by your gross (pre-tax) monthly income, then express the result as a percentage. Lenders use it to gauge how much new mortgage payment you can take on.
The debts counted are the recurring obligations on your credit report and loan file: the proposed housing payment, car loans, student loans, minimum credit-card payments, personal loans, and court-ordered payments like child support. Day-to-day expenses such as utilities, groceries, and insurance are generally not counted. The sample below shows the math with illustrative numbers.
This guide complements the affordability guide, which covers the 28/36 rule of thumb for budgeting a comfortable payment. Here the focus is the qualifying ratios lenders actually underwrite and how to move them.
| Item | Sample monthly amount | Counts in DTI? |
|---|---|---|
| Gross monthly income | $6,000 | Denominator (income) |
| Proposed housing payment (PITI) | $1,500 | Yes, front-end and back-end |
| Car loan | $400 | Yes, back-end |
| Student loan | $150 | Yes, back-end |
| Credit-card minimums | $50 | Yes, back-end |
| Front-end DTI ($1,500 / $6,000) | 25% | Housing only |
| Back-end DTI ($2,100 / $6,000) | 35% | Total debt |
Source: CFPB definition of debt-to-income ratio (as of 2026).
What is the difference between front-end and back-end DTI?
Front-end DTI, also called the housing ratio, is just your proposed housing payment divided by your gross monthly income. The housing payment is principal, interest, property taxes, and insurance, plus any HOA dues and mortgage insurance. In the sample above, that is $1,500 divided by $6,000, or 25 percent.
Back-end DTI, also called the total debt ratio, adds all your other monthly debt payments to the housing payment before dividing by income. In the sample, that is $2,100 divided by $6,000, or 35 percent. The back-end ratio is the one most programs weigh most heavily, because it reflects everything you owe, not just the house.
Related: How much house can you afford (the 28/36 guideline), What affects your mortgage rate
What DTI do mortgage lenders actually require?
There is no single DTI cap that applies to every loan. The qualifying line depends on the program, on the automated underwriting system (AUS) result, and on your compensating factors, such as strong reserves, a high credit score, or a low loan-to-value. The table sets out where each program's line sits and how it is applied.
One point worth clearing up: 43 percent is often cited as a hard cap, but it is not a current universal limit. The General Qualified Mortgage standard under Regulation Z (12 CFR 1026.43) moved to a price-based test, measured by the spread between the loan's APR and a benchmark rate, rather than the old hard 43 percent DTI line. So 43 percent is a useful reference point, not a rule that decides every file.
Because the automated underwriting result and compensating factors drive the real answer, two borrowers with the same DTI can get different outcomes. The most reliable way to know where you stand is to have a loan officer run your file, not to compare yourself to a single number.
| Loan program | Reference point | How it is applied | Source |
|---|---|---|---|
| Conventional (Fannie Mae / Freddie Mac) | Commonly up to about 50% back-end | AUS-driven with compensating factors; not a hard cap | Fannie Mae and Freddie Mac automated underwriting |
| FHA | About 31% front-end / 43% back-end (manual) | Manual-underwrite reference points; higher allowances are common with AUS approval and compensating factors | HUD Handbook 4000.1 |
| VA | No strict DTI cap | Residual income is the primary method; DTI is a secondary guideline | VA Pamphlet 26-7 |
| Qualified Mortgage (ATR/QM) | No hard 43% DTI line | General QM is price-based (APR spread), not a fixed DTI cap, since 2021 | Regulation Z, 12 CFR 1026.43 |
Source: Fannie Mae / Freddie Mac; HUD Handbook 4000.1; VA Pamphlet 26-7; Regulation Z 12 CFR 1026.43 (as of 2026).
How can I lower my DTI before applying for a mortgage?
You lower DTI either by reducing the monthly debt payments that count or by documenting more qualifying income. Each lever below could help, but the effect depends on your specific file, so treat them as options to discuss, not guarantees.
A lower DTI can widen your options, but it is one factor among several, including credit, reserves, and the property. If your ratio is close to a program's comfort zone, a loan officer can tell you which single move would help your file the most before you make it.
- Pay down revolving balances. Lowering credit-card balances reduces the minimum payments that count in your back-end ratio, and it can help your credit score at the same time.
- Avoid opening new debt before and during the loan. A new car loan or credit line adds a monthly payment and can change your ratio mid-process, so it is best to wait until after closing.
- Pay off or pay down small installment loans near payoff. Some programs let you exclude an installment loan with only a few payments left, so retiring it can remove that payment from the ratio.
- Consider a qualified co-borrower. Adding a co-borrower with income and manageable debt can improve the combined ratio, though their debts count too, so it has to net out in your favor.
- Document additional qualifying income. Stable bonus, overtime, part-time, or self-employment income may count if it is documented and meets the program's history requirements; this is where the right paperwork matters.
- Restructure or consolidate higher-payment debts. Replacing several high-minimum-payment debts with one lower monthly payment can reduce the back-end ratio, though you should weigh total interest and the trade-offs before consolidating.
Related: Self-employed borrowers: documenting variable income, Debt consolidation: weigh the trade-offs first
Frequently asked questions
Glossary
- Debt-to-income ratio (DTI)
- Your total monthly debt payments divided by your gross monthly income, expressed as a percentage; a core measure lenders use to gauge how much payment you can take on.
- Front-end (housing) ratio
- Your proposed monthly housing payment divided by gross monthly income.
- Back-end (total debt) ratio
- Your housing payment plus all other monthly debt payments, divided by gross monthly income; usually the more heavily weighted ratio.
- Automated underwriting system (AUS)
- The software (such as Fannie Mae's or Freddie Mac's) that evaluates a loan file and returns an approval recommendation, often allowing higher DTI with compensating factors.
- Compensating factors
- Strengths in a file, such as large reserves, a high credit score, or a low loan-to-value, that can support a higher DTI.
- Residual income
- The money left each month after the mortgage, debts, taxes, and basic living costs; the primary qualifying method for VA loans.
- Qualified Mortgage (QM)
- A loan meeting the ability-to-repay standards under Regulation Z; the General QM test is now price-based (APR spread), not a fixed 43 percent DTI cap.