Mortgage amortization calculator — instalment, balance and term
How much is left at the end of the fixed-rate period? The calculator shows your payment, the interest cost and the remaining debt — year by year, optionally with an annual extra repayment.
How do you calculate the payment, remaining balance and amortization schedule of a mortgage?
With an annuity loan, the monthly payment stays constant throughout the fixed-rate period; it's made up of an interest and a repayment share, calculated as the interest rate plus initial repayment rate divided by twelve, times the loan amount. Because interest only accrues on the outstanding balance, the split shifts toward repayment year by year — and the effect accelerates over time. What matters most is the remaining balance at the end of the fixed-rate period: it becomes the follow-up financing, at terms nobody knows today. A higher initial repayment rate or regular extra payments reduce that balance significantly, lowering the follow-up risk. The calculator below shows the payment, interest cost and the full year-by-year amortization schedule, optionally with extra repayments. Not legal or tax advice.
With an annuity loan the payment stays constant; each year the interest share falls and the repayment share rises. A higher initial repayment rate or regular extra repayments noticeably reduce the remaining debt at the end of the fixed-rate period — and thus the follow-up risk. Enter interest and repayment yourself; the result is your calculation.
Your repayment path
Enter loan amount, interest, initial repayment and fixed-rate period; optionally an annual extra repayment.
| Year | Interest | Repayment | Extra repayment | Remaining debt |
|---|
Non-binding guidance. Annuity loan with a constant payment; extra repayments are only possible within the contractually agreed scope. Interest and repayment are your assumptions — concrete terms arise in an offer.
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Follow-up financing
What happens to the remaining debt after the fixed-rate period — and how switching banks helps.
Follow-up financing →Frequently asked questions about repayment
Why does the interest share fall over the years?
Are extra repayments worthwhile?
What happens at the end of the fixed-rate period?
Keep this result — and the right documents
A calculator gives you a number. A financing decision needs the right paperwork ready before you talk to a bank. We'll send you the checklist that matches your situation — free, no sales call attached.
New: The amortisation schedule also comes as an Excel file to keep — with your figures and all formulas intact. Change the rate, the repayment or the overpayment and the whole plan recalculates. Not a frozen printout.
Need the blank forms right now? Get them via a quick form: self-disclosure form (DE/EN) · net-worth statement (DE/EN).
Open the file directly — no form: Germany property financing checklist (PDF, 7 pages) · Non-resident mortgage checklist (PDF, 8 pages) · KfW funding overview 2026 (PDF, 2 pages) · Amortisation calculator (Excel)