Number format: this calculator uses German notation throughout — a comma is the decimal separator and a dot groups thousands. “1.234,56” means one thousand two hundred thirty-four euros and fifty-six cents. The figures come from German tax law, so they are shown the way German authorities write them.
Fixed-rate period (Zinsbindung)
The period for which the nominal rate is fixed; afterwards the residual debt needs follow-on financing.
In plain language
The fixed-rate period is the time during which your interest rate cannot change — usually ten or fifteen years. After that the loan is almost never repaid: a residual debt remains, for which you need a new contract at whatever rate applies then. How large that residual debt will be is decided today, through the repayment rate.
In detail
The fixed-rate period sets the interest rate for a fixed time; it is not an agreement about the term. When it expires only the rate commitment ends, not the loan — the residual debt continues through a prolongation or a switch of lender. Under § 489 (1) no. 2 BGB the borrower may terminate ten years after full receipt with six months' notice, regardless of a longer fixed period; that caps the downside risk of a very long commitment. The size of the residual debt at the end depends almost entirely on the repayment rate, because early on the repayment share of the instalment is small. A long fixed period usually costs an interest premium — it is insurance against rising rates and, like any insurance, not free.
Worked example
250.000 € at 3,75 % with 2 % initial repayment: after a ten-year fixed period 189.447,36 € is still outstanding — so in ten years only about 60.550 € was repaid, although 143.750 € was paid in instalments. The rest was interest. With 3 % initial repayment the residual debt would be 159.171,85 €, roughly 30.000 € lower.
In brief
The residual debt at the end of the fixed period is shown — it depends on the repayment share, small at the start.
Legal basis: § 489 BGB · as at 2026