Debt-to-income ratio calculator
Work out the share of your income that goes on debt and housing, and how lenders read it.
About the debt-to-income ratio calculator
Work out the share of your income that goes on debt and housing, and how lenders read it.
Part of SmartCalcy’s mortgage & real estate tools. It runs in your browser with no account, uses your own currency and units (change them at the top of the page), and gives estimates for information only, so check official guidance before you rely on a result.
How to use the debt-to-income ratio calculator
What it calculates and when to use it
Your debt-to-income ratio compares monthly debt payments with gross monthly income. Mortgage lenders use it to judge whether you can take on more borrowing.
How to use it, step by step
- Enter gross monthly income, before tax.
- Enter your rent or mortgage payment.
- Add the monthly payments on cars, cards, student loans and other debts.
- Read the front-end and back-end ratios and the room left under 36% and 43%.
What each input means
- Gross income per month – Income before tax and deductions.
- Rent or mortgage – Your housing payment.
- Debt payments – Minimum payments on car, card, student and other debts.
How to read the results
- Housing ratio (front-end) – Housing payment ÷ gross income.
- Total debt ratio (back-end) – All debt payments including housing ÷ gross income.
- Room left – Extra monthly debt you could take before hitting 36% or 43%.
The formula
Front-end ratio = housing payment ÷ gross monthly income. Back-end ratio = (housing + all other debt payments) ÷ gross monthly income. Both are multiplied by 100 for a percentage.
A worked example
Income of 5,000 a month, housing of 1,300 and other debts of 500. The housing ratio is 26% and the total ratio is 36%, so there is no room left under 36% but 350 under 43%.
Assumptions and limits
- Everyday spending such as food and utilities is not counted.
- Lenders set their own limits; 36% and 43% are common reference points, not rules.
Common mistakes
- Using take-home pay instead of gross.
- Leaving out minimum payments on cards or student loans.
- Counting the new mortgage twice when you are replacing rent.
Frequently asked questions
What is a good debt-to-income ratio?
36% or lower is usually viewed as comfortable. Above 43% many lenders will refuse or limit a mortgage.
Does DTI affect my credit score?
No. Credit scores do not include income, but lenders look at both.
Related tools
Details
- Housing ratio (front-end)
- 26%rent or mortgage ÷ income
- Total debt ratio (back-end)
- 36%all debts ÷ income
- Room left up to 36%
- £0.00more monthly debt
- Room left up to 43%
- £350.00
- Debt payments excluding housing
- £500.00