French Borrowing Power Calculator: Mortgage Capacity (35%)

Borrowing capacity: the calculation from 35% of income

Borrowing capacity is the amount a maximum monthly payment can repay over the chosen term. The tool sets that payment at 35% of your monthly net income minus your existing loan payments, then converts it into a loan amount with the present-value formula. With 3,000 of income, 1,050 a month over 20 years at 3.9% supports a loan of about 174,800.

The formula

Maximum payment = net income × 35% − existing loan payments. Capacity = payment × (1 − (1 + r)^−n) / r, with r = annual rate / 12 and n the number of months. The total budget adds your down payment to that capacity.

Worked example

Income of 3,000 a month, no other loans, 20,000 down, 20 years at 3.9%. Maximum payment: 1,050. Capacity: 174,789, total budget: 194,789. Over 25 years, capacity rises to 201,022. A 200 monthly car loan cuts the payment to 850 and the 20-year capacity to 141,496.

What the tool leaves out

• The 35% cap is fixed and applied entirely to principal and interest. The French rule, however, includes borrower insurance: with insurance at 0.30% of the loan per year, the same 1,050 only finances about 167,800. The result therefore slightly overstates what a French bank will lend.
• The term slider goes up to 30 years, beyond the 25-year regulatory cap.
• No notary fees, guarantee costs or remaining-income check. To test whether a specific project meets the rules and leaves enough to live on, use the site's HCSF debt-to-income calculator.

An indicative 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, and a maximum term of 25 years (27 years with a deferral of up to 2 years, for example for off-plan purchases or new builds). Rules kept unchanged by the HCSF in 2026. (checked 14/10/2026)

Frequently Asked Questions

How much can I borrow on a net salary of 3,000 a month?

Under the 35% rule your maximum payment is 1,050. At 3.9% that supports about 174,800 over 20 years and 201,000 over 25 years, excluding borrower insurance. Every existing loan payment reduces the available amount one for one.

Is the 35% debt-to-income cap mandatory in France?

Yes for French banks since 1 January 2022: decision D-HCSF-2021-7 of the High Council for Financial Stability caps the debt-service ratio at 35% of net income, insurance included, and the term at 25 years. Banks may exceed it only for a limited share of their new mortgages, mainly for main-residence buyers.

Why does my bank offer less than this simulator?

The tool puts the full 35% towards principal and interest, while the rule includes borrower insurance. With insurance at 0.30% a year, a total payment of 1,050 over 20 years at 3.9% finances about 167,800 instead of 174,800. Banks also check what you have left to live on and how stable your job is.

Does a longer term increase borrowing capacity much?

Yes: at 1,050 a month and 3.9%, capacity rises from 174,789 over 20 years to 201,022 over 25 years, about 15% more. The slider goes up to 30 years (222,614), but a French bank cannot normally go beyond 25 years, or 27 with a deferral.

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.