Debt-to-Income Ratio Calculator
Work out your back-end and front-end DTI from gross monthly income, housing payment, and other monthly debts. Uses the standard CFPB / Fannie Mae definition that mortgage underwriters apply.
Back-end DTI
33.33%
- Front-end (housing) DTI
- 25%
- Total monthly debt
- £2,000.00
- Gross monthly income
- £6,000.00
- Residual income (gross)
- £4,000.00
Back-end DTI is the share of your gross monthly income that goes to all recurring debt — housing plus auto, student, credit-card minimums, and any other reported loan payment. Lender thresholds (US): conventional conforming up to 45–50% with compensating factors, FHA up to 43% (sometimes 50%), VA benchmark 41%, USDA 41%. Front-end (housing only) DTI is the sister figure most lenders also cap, typically at 28–31%. Lower is always better — a DTI under 36% is the textbook "comfortable" zone.
How to use this calculator
Enter three numbers. Gross monthly income is your pre-tax pay (salary divided by 12, plus any reliable bonus, commission, or self-employment income an underwriter would accept). Housing payment is your full PITI — principal, interest, property taxes, and insurance — if you own, or contractual rent if you do not. Other monthly debt is the sum of every minimum required payment that appears on your credit report: auto loans, student loans, personal loans, and the minimum due on credit cards. Skip utilities, phone, groceries, and other discretionary spending — DTI excludes them by definition. The calculator returns back-end DTI (all debts), front-end DTI (housing only), total monthly debt, and the residual income left after debt payments.
How the calculation works
DTI = total monthly debt payments / gross monthly income, expressed as a percentage. The front-end variant uses only the housing payment in the numerator; the back-end variant uses housing plus every other recurring debt. Underwriters lean on the back-end figure as the headline qualification number. Standard thresholds: conventional conforming loans (Fannie Mae / Freddie Mac) up to 45%, stretching to 50% with strong compensating factors; FHA up to 43%, sometimes 50%; VA uses 41% as a benchmark backed by a residual-income check; USDA 41%. UK lenders rely on Loan-to-Income and an MCOB stress test instead, but the same DTI math is a useful self-check before applying.
Worked example
A borrower earns $6,000 per month gross. Mortgage PITI is $1,500. Auto loan $300, student loan $150, credit-card minimums $50 — $500 in other debt. Total monthly debt = $1,500 + $500 = $2,000. Front-end DTI = 1,500 / 6,000 = 25%. Back-end DTI = 2,000 / 6,000 = 33.33%. Both sit comfortably inside Fannie Mae limits and well inside the 43% Qualified Mortgage ceiling — this borrower would qualify on DTI for most conforming products.
Frequently asked questions
What counts as debt in the DTI calculation?
Anything that appears as a recurring credit obligation on your credit report: mortgage or rent, auto loans, student loans, personal loans, credit-card minimum payments, secured lines of credit, child support, and alimony. Lenders specifically exclude utilities, mobile phone, broadband, insurance premiums other than what is escrowed into the mortgage, groceries, and other discretionary spend. The principle is "what would still be due if you stopped spending tomorrow" — that is the debt that has to come out of income before any flexibility starts.
What is the difference between front-end and back-end DTI?
Front-end DTI uses only the housing payment in the numerator (mortgage PITI or rent). Back-end DTI uses housing plus every other recurring debt. Underwriters cap both, but the back-end number is the headline qualification figure. Typical caps: front-end 28–31%, back-end 43% for FHA, 45% conforming (stretching to 50% with strong reserves, credit, or down-payment). The gap between the two tells a lender how leveraged you are on non-housing debt.
What is a good DTI ratio?
Below 36% is the textbook "comfortable" band — quoted by the CFPB and most personal-finance sources. 36–43% is fine for most conforming and government-backed mortgages. 43% is the Qualified Mortgage ceiling for many products. Above 50% is increasingly hard to finance and signals that debt servicing leaves little room for emergencies, retirement saving, or rate rises. Lower is always better; aim under 36% if you have flexibility on either side of the ratio.
Does DTI use gross or net income?
Gross — pre-tax income. Lenders use gross because tax withholding varies by jurisdiction, filing status, retirement contributions, and benefits elections, so net is not comparable across applicants. The trade-off is that a 43% DTI on gross income can feel much tighter on a take-home basis once tax and benefits come out. When budgeting personally rather than qualifying for a loan, it is worth recomputing the same numerator against net pay to see what the cash-flow picture actually looks like.
How can I lower my DTI quickly?
Three levers, in roughly increasing order of difficulty. Pay down the credit-card balance with the highest minimum payment — this is the fastest way to drop the numerator. Avoid taking on new debt in the 60–90 days before applying for a mortgage; even a soft inquiry plus a new tradeline can shift a borderline application. Increase the documented numerator on the income side: count bonus and commission that has a two-year track record, add a co-borrower, or close on the new mortgage after a documented raise. Selling a financed asset (car, boat) and clearing its loan removes the payment from the back-end calculation immediately.
Does the DTI calculation work outside the US?
The math is universal — debt divided by income — but the regulatory framing differs. UK mortgage affordability is anchored on Loan-to-Income (LTI) and the FCA MCOB stress test, with DTI used informally as a sanity check. Canadian lenders use Gross Debt Service (GDS) and Total Debt Service (TDS), which are conceptually the same as front-end and back-end DTI with slightly different inclusions. Australian and New Zealand lenders use serviceability ratios that fold in a buffer interest rate. The 36% / 43% benchmarks here are US thresholds; outside the US, treat them as guidance rather than rules.