Loan impact calculator

Uses the standard French (annuity) formula. Default “new rate” is the latest 12-month fixing when the feed loads.

Waiting…

How to use this calculator

Enter the principal still outstanding and the years left — not the original amount unless the loan is new.

Type the contractual spread. The boxes “old” and “new” are 12-month Euribor only; the script adds the spread.

Leave “new” empty until the feed fills the latest fixing, or type the monthly average your letter names.

Key: this is the French (annuity) formula. Fees, insurance and day-count in a real bank engine can differ by a few euros. Use it to see the direction and the size of a review, not as a notary exhibit.

Search phrases this tool supports: floating-rate loan calculator, how a 12-month Euribor move changes a payment, current Euribor rate into an installment. For quarter-point steps use payment delta. For history years use year lookup.

Live print: Euribor today. Method: how Euribor affects a loan.

What this calculator is doing

Payment = French annuity. Rate per month = (Euribor + spread) / 12. That is the same shape most euro household loans use. It is not a 360-day money-market quote and it is not a U.S. 30-year fixed quote.

Search Console already shows this URL in the United States and the United Kingdom. If the loan is in euro and names 12-month Euribor, this is the right engine. If the loan is a dollar SOFR note, it is not.

Three clocks on one loan: daily vs monthly average. Add only the margin: spread builder.

Informational. Fees, floors and insurance sit outside the box.