Questions to Ask About Debt-to-Income Ratio

Debt-to-income ratio — DTI — is one of the first numbers a lender calculates and one of the least understood by borrowers. These questions will make it concrete before you apply.

What exactly is DTI?

DTI is your total monthly debt payments divided by your gross monthly income, expressed as a percentage. Lenders use it to judge whether your budget has room for another payment. Ask any lender you are considering what DTI range they are comfortable with for your loan type — thresholds vary by product and lender.

Which debts count?

Ask the lender to specify: typically it includes rent or mortgage payments, car loans, student loans, credit card minimums, child support, and alimony. Everyday expenses like groceries, utilities, and insurance premiums generally do not count. Knowing the exact list lets you calculate your own DTI the way the lender will.

Is it calculated before or after tax income?

Lenders generally use gross (pre-tax) monthly income. If your income varies — commissions, overtime, freelance — ask how the lender averages it; many use a 12- or 24-month average, and some discount variable income. Self-employed borrowers should ask what documentation establishes the income figure.

What is the difference between front-end and back-end DTI?

For mortgages, lenders often look at two ratios: front-end (housing costs alone versus income) and back-end (all debts versus income). Ask which one matters more for your loan program and what limits apply to each. Improving either ratio strengthens your application.

How can I improve my DTI before applying?

The levers are straightforward: pay down debt balances (which lowers minimum payments), avoid taking on new debt, and document all income sources the lender will count — a second job, regular bonuses, rental income. Ask the lender to rerun the numbers after any paydown; a DTI that crosses under a threshold can change both approval and pricing.