Introduction
Debt-to-income ratio, or DTI, is total monthly debt payments divided by gross monthly income. Lenders use it as one check, alongside credit history and deposit, when deciding whether a payment is affordable.
Quick answer
- DTI = monthly debts ÷ gross monthly income × 100.
- Lower is generally viewed as more manageable.
- Lenders use their own definitions and thresholds.
What is it?
Add up monthly debt payments — mortgage or rent is often included by lenders, plus loans, cards and other fixed debts — then divide by gross income, before tax.
How to use the calculator, step by step
- Enter your numbers in the calculator linked above.
- Press Calculate.
- Check the main result and the total, not just the first number.
- Try a second version — a different rate, term or payment — and compare the totals.
Worked example
Monthly debts £800, gross income £4,000: DTI 20.0%.
Common mistakes
Using net income instead of gross; leaving out a debt; treating a planning figure as an approval.
Frequently asked questions
Is the calculator result exact? No, it is an estimate for learning and planning, based on the numbers you enter and the assumptions stated on the calculator page.
Should I check with a professional? Yes, for a mortgage, loan, tax or investment decision, check with your lender, bank, tax authority or a qualified adviser before you decide.
Can I use this in the US, UK or Canada? The maths is the same, but rates, tax bands and lender rules differ by country. Use the numbers and rules for your country, and check the official source where a rate or band matters.
Conclusion and next step
Try your own numbers in the calculator, compare the totals, and read the next calculator guide from the homepage when you are ready.
Disclaimer: This article and calculator are for information and education only. Results are estimates and not financial advice. Please check with your lender or a qualified adviser before making a financial decision.