What is Debt-to-Income (DTI)?
Debt-to-Income (DTI) is the ratio of monthly debt payments to gross monthly income, expressed as a percentage. It is the primary affordability test US mortgage lenders use; the CFPB's Qualified Mortgage rule generally caps back-end DTI at 43 percent. Front-end DTI captures only housing costs; back-end DTI includes all recurring debt.
Detailed definition
DTI is the US lending system's single most-used affordability metric. The numerator is monthly debt service; the denominator is gross monthly income. Underwriters use it because empirically, borrowers whose debt service is a small share of income default less. The metric became central after the 2010 Dodd-Frank Act, which required the Consumer Financial Protection Bureau to define the "Qualified Mortgage" (QM) standard. The CFPB's Regulation Z amendment (12 CFR 1026.43) made a 43 percent back-end DTI ceiling a safe harbour: loans at or below it get the legal presumption of compliance with the Ability-to-Repay rule.
There are two distinct DTI ratios. Front-end DTI (sometimes called the housing ratio) captures just the proposed housing payment: principal, interest, property taxes, homeowner's insurance, mortgage insurance, and HOA dues (PITIA). Back-end DTI captures housing plus all other recurring debt: auto loans, student loans (with special rules for income-driven repayment), credit card minimum payments, personal loans, court-ordered child support, alimony, and any cosigned debt the borrower actually services. The back-end number is the harder underwriting hurdle; most rejections are back-end driven.
Income definition matters. DTI uses gross (pre-tax) monthly income because that is the standardised denominator the federal forms can verify. For W-2 wages, lenders average the last two pay stubs or use the YTD divided by months elapsed. For self-employed income they require two years of tax returns and use the average net income (with depreciation added back per Fannie Mae rules). Bonus, overtime, and commission income require a 2-year track record to count fully. Side-gig and rental income have separate documentation rules.
Formula
Front-end DTI = (Proposed PITIA) / Gross monthly income x 100 Back-end DTI = (Proposed PITIA + All other monthly debt) / Gross monthly income x 100 PITIA = Principal + Interest + Taxes + Insurance + (HOA + PMI if applicable)
- Proposed PITIA = the new mortgage payment plus escrows (taxes, insurance) plus HOA dues. Used in both ratios.
- All other monthly debt = auto, student, credit card minimums, personal loans, child support, alimony, cosigned debt actually paid.
- Gross monthly income = pre-tax W-2 wages, self-employment net per tax returns, plus qualified non-wage income with the required track record.
- Excludes: utilities, groceries, fuel, gym, streaming, term life, disability insurance, health insurance premiums (employer-deducted).
Worked example (2026 conventional mortgage qualification)
Suppose a 2026 household has $9,000 gross monthly income, is looking at a $500,000 home with a $400,000 conventional mortgage at 6.50 percent, $4,800 annual property tax, $1,800 annual homeowner's insurance, $360 monthly HOA, $0 PMI (80 percent LTV).
- Proposed PITI: $2,528 principal and interest + $400 tax + $150 insurance = $3,078.
- Proposed PITIA: $3,078 + $360 HOA = $3,438 per month.
- Front-end DTI: $3,438 / $9,000 = 38.2 percent.
- Other monthly debt: $450 auto + $250 student + $90 credit card minimums = $790.
- Back-end DTI: ($3,438 + $790) / $9,000 = 47.0 percent.
- Result: Back-end at 47 percent exceeds the 43 percent QM safe-harbour. Conventional approval still possible with compensating factors (high FICO, large reserves) or by paying off the $250 student loan, which drops back-end DTI to 44 percent.
US DTI thresholds by loan program
| Loan program | Preferred back-end DTI | Maximum back-end DTI | Notes |
|---|---|---|---|
| Conventional QM (Fannie / Freddie) | 36 percent or less | 50 percent with compensating factors (Desktop Underwriter approval) | 43 percent is the CFPB QM safe-harbour line |
| FHA | 43 percent | 50 to 56.9 percent with strong compensating factors | Lower FICO floor (580); MIP for life of loan |
| VA | 41 percent typical guideline | 60 percent+ if residual income test is passed | VA uses regional residual-income tables |
| USDA Rural Development | 29 percent front-end / 41 percent back-end | Up to 44 percent with strong compensating factors | Income-limited program |
| Non-QM / jumbo | Varies; often 43 percent | Can exceed 50 percent at higher rates / lower LTV | Non-QM loans lack the QM safe harbour |
Related terms
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Frequently asked questions
What is a good DTI ratio?
For US mortgage underwriting, back-end DTI of 36 percent or below is considered comfortable. The CFPB's Qualified Mortgage rule generally caps back-end DTI at 43 percent for the safe-harbour QM definition. Above 43 percent borrowers can still qualify under FHA (up to 50 percent), VA (up to 60 percent with residual income), or conventional with strong compensating factors.
What is the difference between front-end and back-end DTI?
Front-end DTI (housing ratio) includes only proposed housing costs: principal, interest, property taxes, homeowner's insurance, mortgage insurance, and HOA dues (sometimes called PITIA). Back-end DTI includes housing plus all other monthly debt: auto loans, student loans, credit card minimums, personal loans, child support, and alimony. Lenders care more about back-end DTI.
Does DTI include utilities or groceries?
No. DTI excludes recurring living expenses like utilities, groceries, fuel, gym memberships, streaming subscriptions, and most insurance premiums. Only debt service counts. Property taxes, homeowner's insurance, and HOA are included only because they are bundled into PITIA on the front-end housing ratio.
How can I improve my DTI?
Two levers: reduce monthly debt or raise income. Pay off small installment loans entirely (lender removes the line), pay down credit card balances below the minimum-payment trigger, refinance a high-rate auto loan, or close out a co-signed debt that you do not actually pay. On income, document raises, bonuses, or side-gig income that has a 2-year history.
Does DTI include rent?
When a mortgage application is in process, the proposed new mortgage payment replaces current rent in the DTI calculation; current rent is not added on top. For non-mortgage credit decisions (cards, auto loans), rent or current housing cost typically is included in the back-end ratio because the underwriter wants to see the full obligation picture.
What if my DTI is over 43 percent?
You still have options. FHA loans allow up to 50 percent back-end DTI with compensating factors. VA loans use residual-income tests in addition to DTI and can go above 60 percent. Conventional underwriting can stretch above 43 percent with high reserves, high FICO, and a low LTV. Paying down or paying off one card or installment loan often drops DTI several points fast.
Sources and further reading
- Consumer Financial Protection Bureau, 12 CFR 1026.43 - Ability-to-Repay and Qualified Mortgage.
- CFPB, What is a debt-to-income ratio?.
- Fannie Mae, Selling Guide B3-6-02: Debt-to-Income Ratios.
- HUD, FHA Single Family Handbook 4000.1 - Income and DTI.
- VA, VA Lender's Handbook M26-7 - Residual Income and DTI.