Debt-to-Income Ratio Calculator

Calculate your debt-to-income ratio - the key metric lenders use when assessing mortgage and loan applications. See how your DTI compares to lender thresholds and what it means for your borrowing.

Last updated: April 2026

Your income & debts
Before tax. Include all regular income sources.
Your DTI ratio
Debt-to-income ratio
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Total monthly debt payments -
Remaining monthly income -
Lender assessment -

What is debt-to-income ratio?

Your debt-to-income (DTI) ratio is the percentage of your gross monthly income that goes toward debt payments. It is one of the key metrics lenders use when assessing mortgage and loan applications. A lower ratio indicates you have more income relative to your debt obligations, which lenders view as lower risk.

What DTI ratio do lenders want?

UK mortgage lenders typically prefer a total DTI (including the proposed mortgage) of no more than 43–45%. Many mainstream lenders use an affordability-based assessment rather than a strict DTI cap, but the principle is the same: total committed debt payments should leave you with enough disposable income to meet living costs. A DTI above 50% will generally make mortgage approval difficult with high-street lenders, though specialist lenders exist for borrowers in this position.

How to improve your DTI ratio

The two levers are increasing income or reducing debt payments. Paying off smaller debts entirely removes that monthly commitment from the calculation. Consolidating multiple debts into a single lower-rate loan can reduce the total monthly payment. Increasing your income through a pay rise, promotion, or additional work also improves the ratio. Before a mortgage application, lenders may ask you to close unused credit card accounts, as the available credit (even unused) is factored into their assessment.

Frequently asked questions

Your DTI ratio is not directly recorded in your credit file - credit reference agencies do not see your income. However, lenders calculate it themselves during an application using your income information and the debt payments visible on your credit report. A high DTI will typically result in a declined application or a lower loan amount offered, even if your credit score is good.
All regular committed monthly payments count: mortgage or rent, personal loans, car finance (PCP or HP), student loan repayments (these are included by most lenders), credit card minimum payments, hire purchase agreements, and any other formal lending. Regular bills (utilities, insurance, subscriptions) do not count as debt payments for DTI purposes, though lenders do consider them in their broader affordability assessment.
UK mortgage lenders must follow FCA responsible lending rules. Most use a combination of: income multiples (typically 4–4.5x gross annual income), affordability modelling (stress-tested at a higher rate, usually 3% above the initial rate), and existing debt commitments. Lenders look at your net disposable income after tax, essential bills, and debt payments. The mortgage payment at a stressed rate must fit comfortably within your disposable income.

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