Loan calculator

The annuity stays the same, its composition does not

With an annuity loan you pay the same amount every month. At the start most of it is interest and little is repayment; with every instalment the outstanding debt falls, so the interest share falls — and the repayment share grows. The schedule shows that month by month and can be downloaded in full as CSV.

The effective annual rate under § 16 PAngV is the only comparable figure

It contains one-off costs and the timing of payments and is found iteratively: what is sought is the rate at which the present value of all payments comes to zero. Two offers with the same nominal rate can have different effective rates — which is why the nominal rate alone is no basis for comparison.

After the fixed-rate period a new loan begins

The fixed-rate period secures the nominal rate only for its own duration. After that the residual debt continues at an unknown rate. The calculator computes this follow-on financing with the same function and sets against it what would have accrued at today's rate throughout. The rate assumed is an assumption, not a forecast — it shows how sensitive the financing is.

Example: 250.000 €, 3,75 % nominal, 2 % initial repayment, 10-year fixed period

Monthly instalment	1.197,92 €
Debt outstanding after 10 years	189.447,36 €
New instalment at 5,5 %	1.374,43 €
Extra interest from the new rate	38.561,54 €

After ten years only around 60.000 € has been repaid — and a follow-on rate 1,75 points higher costs 176,51 € more per month. Choosing a shorter fixed period buys a lower rate at the price of this risk.

What this calculator does not cover

Pretending to be complete is the costliest mistake a financial calculator can make. These points are deliberately absent — either because they need details this page does not ask for, or because they cannot be substantiated in general terms:

• Commitment interest on undrawn parts of the loan, and partial drawdowns during a construction phase.
• The early repayment charge (Vorfälligkeitsentschädigung) — it depends on the remaining term and on reinvestment rates.
• Tax effects for let property: there, loan interest is a deductible expense.

Related calculators

• Purchase costs — what has to be financed on top of the purchase price
• Compound interest calculator — the same interest arithmetic from the other side: saving instead of owing
• Gross to net — which instalment your net pay actually supports