Debt to Income Calculator

Free Debt to Income Calculator: calculate debt to income instantly with transparent formula, worked examples and tips. No signup.

The debt-to-income (DTI) ratio expresses your total monthly debt payments as a percentage of your gross monthly income. It is the primary measure mortgage lenders, banks, and credit providers use to assess whether you can afford additional debt. A low DTI indicates financial health and borrowing capacity; a high DTI signals that a large proportion of income is already committed to debt repayment, reducing the ability to manage new obligations. Loan Payment Calculator and Mortgage Calculator are closely related affordability tools.

Understanding your DTI before applying for a mortgage, car loan, or personal loan shows how lenders will view your application — and what steps you might take before applying to improve your chances of approval at the best rate. Most major lending markets use DTI thresholds as one of the primary affordability criteria alongside income multiples and credit scores.

List all monthly debt payments: mortgage or rent, car finance, personal loans, student loans, credit card minimum payments, hire purchase agreements.
Enter the total of all monthly debt payments.
Enter your gross monthly income (before tax) — include all sources: salary, self-employment income, rental income.
DTI ratio = total monthly debt ÷ gross monthly income × 100.
Calculate both front-end DTI (housing costs only ÷ income) and back-end DTI (all debt ÷ income) separately for a complete picture.
If your DTI is above 36–43%, explore debt reduction strategies before applying for new credit.

Debt-to-income ratio formula

DTI % = (Total monthly debt payments ÷ Gross monthly income) × 100

Front-end DTI = Housing costs only ÷ gross income × 100

Back-end DTI = All monthly debt payments ÷ gross income × 100

Worked example: Gross monthly income 4,500. Monthly payments: mortgage 1,200 + car finance 250 + personal loan 150 + credit card minimum 60 = 1,660 total. Back-end DTI = 1,660 ÷ 4,500 × 100 = 36.9%. Front-end DTI = 1,200 ÷ 4,500 × 100 = 26.7%.

Interpreting your DTI result

Lender DTI benchmarks

Standard DTI thresholds used by most lenders: below 20% — excellent, strong borrowing capacity; 20–35% — good, well within normal lending criteria; 36–43% — acceptable for many lenders but some may restrict products or require higher deposits; 43–50% — high, many lenders will decline or require compensating factors such as large deposit or excellent credit history; above 50% — very high, most mainstream lenders will decline. Always check your specific lender's criteria, as thresholds vary by institution, country, and loan type.

Finance tips and best practices

Pay off smaller debts before applying for a mortgage — eliminating a car payment reduces your DTI and removes that liability from lender assessments.
Increase income where possible — a pay rise or additional income directly reduces DTI and improves affordability assessments.
Do not apply for new credit in the months before a mortgage application — new commitments raise DTI and leave hard searches on your credit record.
Joint applications combine both incomes and both debts — model whether a joint or sole application produces a better DTI for your specific situation.
Lenders may calculate minimum credit card payments differently (some use full balance × 3%, others use the contractual minimum) — ask your mortgage broker how they calculate this.

The generally accepted maximum back-end DTI for qualified mortgage loans in the US is 43% (FHA guidelines); in the UK, lenders conduct individual affordability assessments with similar effective limits.
A DTI reduction from 45% to 35% typically unlocks a significantly wider range of mortgage products and better interest rates in most lending markets.
Each additional 5% of DTI above 40% roughly doubles the likelihood of mortgage application rejection, based on lender data from multiple markets.
Paying off a 200/month car loan before a mortgage application reduces DTI by approximately 4.4% for someone earning 4,500/month — potentially moving them from a borderline to acceptable DTI band.

Common mistakes to avoid

Using net (after-tax) income instead of gross income — DTI is always calculated on gross income; using net overstates the ratio.
Forgetting all debt obligations — buy-now-pay-later, hire purchase, maintenance payments, and student loan repayments all count toward total monthly debt.
Confusing front-end and back-end DTI — lenders use both; a good front-end ratio does not compensate for a high back-end ratio.
Not stress-testing the DTI at a higher interest rate — if taking a variable rate mortgage, model your DTI with payments at 2–3% above the current rate.

Mortgage affordability assessment requirements vary by country and are typically set by the national financial regulator. Most developed markets require lenders to conduct affordability assessments that include current debt obligations, income verification, and stress-testing at higher interest rates. For mortgage advice, use a regulated mortgage adviser or broker authorised in your jurisdiction. Free financial guidance is available from government-funded money advice services in most countries. This calculator is for planning purposes only and does not constitute financial advice.