Glossary · UK
What is Debt to Income Ratio?
A measure comparing your total monthly debt repayments to your gross income, used by lenders to assess affordability.
Full Definition
The debt to income ratio, often shortened to DTI, compares how much you owe in regular debt repayments against your income. Mortgage lenders use it alongside other affordability checks to judge whether you can comfortably take on new borrowing. It is usually expressed as a percentage, for example total monthly debt payments divided by gross monthly income. Some lenders instead look at total outstanding debt as a multiple of annual income. There is no single legal limit in the UK, and the exact thresholds vary by lender, but a lower ratio generally improves your chances of approval and may unlock better rates. Debts counted typically include credit cards, personal loans, car finance and student loan deductions, while everyday bills such as utilities are assessed separately through expenditure checks. Reducing existing debt before applying, or clearing small balances entirely, can improve your ratio. Lenders also apply a stress test on top, checking you could still afford repayments if interest rates rose. Because criteria differ widely between providers, it is worth comparing several lenders or using a broker rather than assuming one rejection reflects the whole market.