Debt-to-Income Ratio Calculator: 35% Cap and Living Budget

French HCSF debt-to-income ratio: calculation and living budget

Debt-to-income ratio = (existing loans + maintenance paid + new mortgage payment, borrower insurance included) / monthly net income × 100. Since 1 January 2022, French banks must keep it at 35% or less. For a couple earning 5,600 a month with 1,665 of loan charges, the tool finds 29.7%: the project complies with this French rule.

What is calculated

• Income counted: both borrowers' net salaries + 70% of gross rental income + other income.
• Charges: existing loans, maintenance paid, the new mortgage payment and borrower insurance. Current rent is not counted, since it ends with the purchase.
• Living budget: income − loan charges, compared with a benchmark of 950 per adult and 400 per child.
• Payment jump: new payment including insurance − current rent.
• Remaining headroom: 35% of income − existing charges, converted into a loan amount over 25 years at 3.5%.

The gauge is green up to 33%, amber between 33 and 35%, red above.

Worked example (default values)

Salaries of €3,200 and €2,400, two children, a €150 car loan, current rent of €1,100, new mortgage of €1,450 + €65 insurance. Charges: €1,665 for €5,600 of income, i.e. 29.7% (2.7% before the project). Living budget: €3,935, above the €2,700 benchmark. Payment jump: +€415. Maximum payment at 35%: €1,960; headroom for a mortgage: €1,810 a month, about €361,549 of borrowing.

Assumptions to know

• The 70% rental weighting, the living-budget benchmark and the 3.5% rate over 25 years are tool assumptions based on French banking practice, not official rules.
• Banks may exceed 35% for a limited share of their files; the tool does not model this.

This tool checks whether an already-priced project complies; to estimate how much you can borrow from your salary, use the site's borrowing capacity calculator. An estimate that does not replace a bank's or broker's assessment.

Sources and dates: French High Council for Financial Stability (HCSF) decision no. D-HCSF-2021-7 of 29 September 2021, legally binding since 1 January 2022: maximum debt-service ratio of 35% of net income, borrower insurance included, maximum term of 25 years (27 years with a deferral of up to 2 years). Rules kept unchanged by the HCSF in 2026. (checked 14/10/2026)

Frequently Asked Questions

How do I calculate my debt-to-income ratio for a mortgage?

Add up your loan payments (existing and new, borrower insurance included) and any maintenance you pay, then divide by your monthly net income. Example: (150 + 1,450 + 65) / 5,600 = 29.7%. The French HCSF cap is 35%.

Is borrower insurance included in the 35% cap?

Yes. Since decision D-HCSF-2021-7 took effect on 1 January 2022, the 35% debt-service ratio is calculated with borrower insurance included. In the default example, the €65 of insurance is added to the €1,450 payment.

How is rental income counted?

The tool counts 70% of gross rents, a haircut commonly used by French banks to cover vacancies and costs, but not an official rule. Adding €1,000 of rent to the default example puts €700 into income and lowers the ratio from 29.7% to 26.4%.

How much living budget do I need to get a mortgage?

No amount is set by law; each bank has its own benchmarks. The tool compares your remaining income with €950 per adult and €400 per child, so €2,700 for a couple with two children. In the example, €3,935 is left after loan payments, above that benchmark.

What is the payment jump?

It is the difference between your future mortgage payment, insurance included, and your current rent. In the example, €1,515 − €1,100 = +€415 a month. The tool flags it above €400, because a bank will check that you have already been able to save that difference.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.