German Mortgage Calculator (Tilgung)
The monthly rate, the debt left when the fixed rate ends and how long the loan runs.
Good to know. With 1 % initial repayment a German mortgage runs over 40 years. At 3 % it is gone in about 22.
Not financial advice. Uses only the numbers and rates you enter — no live data.
How it works
In plain words
The monthly rate is the loan times the interest rate plus the initial repayment, divided by 12, and it stays the same. Each month interest is charged on what you still owe; the rest of the rate repays the loan. As the debt shrinks, less goes to interest and more to repayment, so the loan is paid off faster than the initial repayment rate suggests.
The formula
Rate = loan × (interest % + repayment %) ÷ 12 Each month: interest = balance × interest % ÷ 12; balance = balance + interest − rate
Worked example
300,000 at 3.6 % interest and 2 % initial repayment: 300,000 × 5.6 % ÷ 12 = 1,400.00 a month. After 10 years you still owe 227,907.14, and at the same rate the loan is paid off in 28 years 8 months.
Sources
- Brealey, Myers and Allen, Principles of Corporate Finance, chapter 2 The standard formulas for loan payments, compounding and present value, the same as a spreadsheet’s PMT and FV.
Sources checked September 29, 2026. 6 automated tests check its answers on every change.
About the german mortgage calculator (tilgung)
German banks don’t usually quote a mortgage by its term. You agree on an interest rate (Sollzins) and an initial repayment rate (anfängliche Tilgung), both as a yearly percentage of the loan, and the monthly rate follows: 300,000 € at 3.6 % interest and 2 % repayment is 5.6 % a year, 1,400 € a month.
The rate stays the same, but its make-up changes. At first most of it is interest. Every payment lowers the debt, so the next month’s interest is smaller and more of the rate goes to repayment. That is why a 2 % initial repayment clears a loan in about 30 years, not 50.
The interest rate is only fixed for the Zinsbindung, commonly 10 or 15 years. When it ends you still owe the remaining debt (Restschuld), and you need a new rate for it, from your bank or another one. The calculator shows that remaining debt and, as a guide, how long the whole loan takes if the rate stayed the same.
A higher repayment rate costs more each month but saves a lot of interest. Many contracts also allow yearly extra repayments (Sondertilgungen), often up to 5 % of the loan, which shorten the term further. Leave a buffer for repairs and changes in income before you choose the highest rate you can afford.
Questions people ask
How is the monthly rate of a German mortgage calculated?
Loan × (interest rate + initial repayment) ÷ 12. 300,000 € at 3.6 % and 2 % is 1,400 € a month.
What is the Restschuld?
The debt that remains when the fixed-rate period ends. You then need a follow-on financing (Anschlussfinanzierung) for it at the rates of the time.
How much initial repayment should I choose?
Many advisers recommend at least 2 %, better 3 %, so the loan is paid off before retirement and the remaining debt stays manageable.
What is a Sondertilgung?
An extra repayment on top of the monthly rate, usually once a year and often up to 5 % of the loan without a fee.