Irish Calculators
Loans & mortgages

Debt-to-Income Ratio Calculator

Calculate debt-to-income ratio using your chosen income basis and total monthly debt payments. Ordinary living expenses are separate, and the result does not determine lending approval.

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Your numbers

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How the calculation works

Debt-to-income expresses regular debt repayments as a share of income over the same period. The gross or take-home selection labels the convention you are using; it does not convert one kind of income into the other or apply a lender approval rule.

DTI = monthly debt payments / monthly income × 100. Weekly income uses 52/12 and fortnightly income uses 26/12.

  1. Put income on a monthly basis

    Annual income is divided by twelve. Weekly and fortnightly figures are multiplied by their annual payment counts and then divided by twelve.

  2. Form the ratio

    Divide total monthly debt repayments by the converted monthly income and multiply by one hundred. Income must be positive so the denominator is meaningful.

  3. Check the underlying amounts

    The breakdown repeats monthly income and monthly debt payments. Verify those two amounts before interpreting the percentage, especially if your pay frequency differs from your repayment frequency.

Worked example: Monthly gross income

Sample inputs demonstrate the method. They are not a forecast or product offer.

The example uses €5,000 monthly gross income and €1,500 monthly debt payments. Dividing €1,500 by €5,000 gives 0.30, which is displayed as 30%. No annualization or tax conversion is needed in that example.

Income amount
5000
Income frequency
Monthly
Income basis
Gross income before tax
Total monthly debt payments
1500

Expected result

Debt-to-income ratio
30%
Monthly income used
€5,000.00
Worked example: Annual income normalized

Sample inputs demonstrate the method. They are not a forecast or product offer.

Income amount
60000
Income frequency
Annual
Income basis
Gross income before tax
Total monthly debt payments
2000

Expected result

Debt-to-income ratio
40%
Monthly income used
€5,000.00

Understanding your result

The result describes repayment pressure under the selected income basis. The same debt produces a higher percentage when divided by a smaller take-home figure.

This ratio omits living expenses and does not establish what a bank will lend. Use a separate household budget to see what remains after food, housing, transport and savings.

Questions you might have

Should I use gross or net income?

Choose the convention you are analysing and keep it visible when comparing ratios; gross and net ratios are not interchangeable.

Choosing the right inputs

Income frequency
Select the frequency of the entered income. Weekly income uses 52 payments per year and fortnightly income uses 26, both converted to a monthly average.
Income basis
Choose gross for income before deductions or net for money received after deductions. Supply the corresponding amount yourself.
Total monthly debt payments
Add contractual monthly debt payments rather than outstanding loan balances. Keep ordinary living expenses outside this debt numerator.

Common mistakes to avoid

  • A yearly debt balance is not interchangeable with a monthly repayment.
  • Ratios calculated from gross and net income should not be compared without identifying the different denominator.

Assumptions to check

  • The result is not a credit decision and does not include ordinary living expenses in the debt numerator.

Sources and method

Read our calculation and testing approach.