Finance · Runs in your browser
Loan amortization calculator
Type the amount, rate and term. The payment, total interest and the full schedule update as you type. No account, nothing uploaded.
The loan
Your result
What an extra payment changes
Leave the extra payment at zero to see the plain schedule.
Amortization schedule
| # | Date | Payment | Interest | Principal | Balance |
|---|
How the numbers are worked out
What you get
The result panel shows the payment per period, the number of payments, total interest, total paid, interest as a share of the amount borrowed, the final payment and the payoff date. The schedule lists every payment with its date, the interest part, the principal part and the balance left. Download it as a CSV file to open in a spreadsheet.
The payment formula
For a rate i per period and n periods, the payment on a principal P is P·i / (1 − (1+i)−n). The rate per period is the annual rate divided by the number of payments per year. At a rate of zero the principal is split evenly across the payments. Some lenders compound differently, Canadian mortgages for example, so their schedule can differ slightly.
Rounding and the last payment
Everything is computed in whole cents and interest is rounded each period. A few cents of drift build up over hundreds of payments, so the final payment absorbs the rest and the closing balance is exactly zero.
Extra payments
An extra amount each period goes to principal and shortens the loan; the regular payment stays the same. The calculator shows the interest saved and how many payments disappear. It assumes the extra payment reaches principal right away and never stops.
What it does not model
The calculator covers loans with a constant payment (annuity loans). It does not handle linear repayment with equal principal parts, rate changes during the term, early repayment fees, taxes, insurance or arrangement fees. The figures are arithmetic on what you enter; your lender's contract decides the real terms.
Questions
What do I need to enter?
The amount borrowed, the annual interest rate and the term in years or months. Optionally you can change the payment frequency (weekly up to once a year), the first payment date, the currency and a fixed extra payment each period.
Can I see the effect of extra payments?
Yes. Enter an extra amount per period and the calculator shows the interest saved, how many payments are removed and the interest you would pay without the extra. With a first payment date set, it also shows the payoff date without the extra. It assumes the extra payment goes to principal right away and never stops.
Which kind of loan does it calculate?
Loans with a constant payment each period, also called annuity loans. Linear repayment with equal principal parts, rate changes during the term, early repayment fees, taxes and insurance are not modelled.
Can I export the amortization schedule?
Yes. Download CSV saves every payment with its period number, date, payment, interest, principal and remaining balance, ready for a spreadsheet.
Is there a limit or an account?
No. This calculator runs in your browser, so there is no daily job count and no account, and nothing is uploaded. The allowance of 3 free jobs a day applies to the tools that process files on the server. Nothing is stored on the server either, so the 24-hour result expiry does not apply here; download the CSV if you want to keep the schedule.
Why is the last payment slightly different?
Interest is rounded to the cent every period. The small differences add up, and the final payment takes up what is left so the balance ends at exactly zero.