Mortgage Amortization Calculator
Full payment-by-payment amortization schedules under the French, German, or American system. Choose a system, enter your loan details, and see every payment laid out — plus the effect of extra payments.
Why the amortization system matters
Before you calculateThe same rate, a different bill
Two loans with an identical rate and term can cost noticeably different amounts in total interest, purely because of how the principal is repaid over time.
Not every payment ages the same
Some systems front-load your payments, others keep them flat, and some defer principal entirely. Knowing which one you're in tells you what to expect next year, not just this month.
Extra payments hit differently
Where a lump-sum or extra monthly payment does the most good — cutting interest, shortening the term, or shrinking a future balloon — depends entirely on the underlying system.
Loan terms
Base details of the mortgage
Summary
Under the French system, every payment stays the same for the life of the loan.
Amortization curve
Outstanding balance over the life of the loan, with and without extra payments
Extra payments
Simulate the effect of extra principal payments. Extras reduce the outstanding balance on top of the schedule, shortening the term or shrinking a final balloon.
Amortization schedule
Payment-by-payment detail
| Date | Payment | Interest | Principal | Extra | Balance |
|---|---|---|---|---|---|
| Calculate the mortgage to see the amortization schedule. | |||||
At a glance
Same loan, three outcomes| System | Payment pattern | Best fit when... |
|---|---|---|
| French | Flat payment, front-loaded interest | You want one predictable number to budget against for the entire term. |
| German | Declining payment, flat principal | You can handle higher payments early and want to minimize total interest. |
| American | Flat interest-only payment, balloon at the end | You need low payments now and a clear plan to cover — or refinance — the balloon later. |
Estimates only, not financial advice. Actual rates, fees, and terms may vary by lender, market, and date — confirm final figures with your bank or financial advisor.