Debt-to-income ratio

The debt-to-income ratio (DTI) measures how much of your income is committed to debt repayments. It’s expressed as a percentage and is one of the headline numbers lenders use to decide whether to lend to you and at what rate.

Two versions

Front-end DTI (housing) — only mortgage or rent payments divided by gross income. Lenders typically want this below 28–30%.

Back-end DTI (total debt) — all monthly debt repayments (housing + student loans + car loans + credit card minimums) divided by gross income. Lenders typically want this below 36–43%.

Formula

DTI = total monthly debt payments ÷ gross monthly income × 100

Use gross (pre-deduction) income for the lender-facing calculation. For your own planning, net income is often more useful because it reflects what’s actually available to spend.

Example

A graduate earning $5,000 gross per month has the following debt repayments: $400 student loan, $300 car loan, $100 credit card minimum. Total = $800.

DTI = $800 ÷ $5,000 = 16%.

That sits well within most lenders’ thresholds, leaving room to take on a mortgage or other borrowing in the future without breaching their limits.

Why it matters

Beyond loan applications, DTI is a useful self-diagnostic. A back-end ratio above 40% leaves little headroom for unexpected expenses — emergency car repairs, medical bills, or a temporary income drop can push the household into deeper borrowing. Below 20%, financial stress around debt is rarely the binding constraint on goals.

For graduates with student loans, DTI typically starts elevated and improves as income grows. Paying off the loan faster (lower monthly payment commitment in the future) and growing income (denominator effect) both help. The student loan payoff calculator shows what extra payments do to the monthly commitment, and the debt consolidation calculator compares strategies for combining multiple debts into a single payment.