See how every payment on a fixed-rate loan or mortgage splits between principal and interest, by month or by year. Add extra payments to see the interest and time you save, and download the full amortization schedule.
How to use the amortization calculator
- Choose your currency, then enter the loan amount, the yearly interest rate, the term in years (and months) and the month of the first payment.
- Optionally open "Extra payments" to add an extra amount every month from a month you choose, a yearly extra, or one-off payments.
- Read the monthly payment, total interest and payoff date, and how much the extras save.
- Switch the schedule between years and months, and download it as a CSV for Excel or Google Sheets.
Amortization formula
Payment = P × r ÷ (1 − (1 + r)^−n), where P is the loan amount, r the monthly rate (yearly rate ÷ 12) and n the number of monthly payments.
Each month: interest = balance × r, principal = payment − interest, and new balance = balance − principal − any extra payment.
Example
200,000 borrowed at 6% for 15 years costs 1,687.71 a month. Over 180 payments you pay 303,788.46, of which 103,788.46 is interest. The first three years look like this:
Interest, principal and the balance at the end of each year.| Year | Interest | Principal | Balance |
|---|
| 1 | 11,769.23 | 8,483.33 | 191,516.67 |
|---|
| 2 | 11,246.00 | 9,006.57 | 182,510.10 |
|---|
| 3 | 10,690.49 | 9,562.07 | 172,948.02 |
|---|
Extra payments compared
The same 200,000 loan at 6% over 15 years.| Extra payments | Total interest | Saved | Paid off after |
|---|
| None | 103,788 | — | 15 years |
|---|
| 200 every month | 85,558 | 18,230 | 12 years 8 months |
|---|
| 2,400 once a year | 86,783 | 17,005 | 12 years 9 months |
|---|
| 10,000 once, in month 24 | 92,638 | 11,151 | 14 years |
|---|
Need weekly or two-weekly payments, fees or an APR? Use the loan calculator. For a home loan with property tax, insurance and PMI, try the mortgage calculator, or the EMI calculator in India.
Frequently asked questions
What is an amortization schedule?
It's a table of every payment on a loan: how much of the payment is interest, how much repays the principal, and the balance left afterwards. With a fixed rate the payment stays the same, but the split changes every month: interest falls and the principal part grows until the loan is paid off.
How is each payment split between interest and principal?
Interest for the month is the balance times the yearly rate ÷ 12; the rest of the payment repays principal. A 200,000 loan at 6% over 15 years has a payment of 1,687.71. In month 1 the interest is 200,000 × 0.06 ÷ 12 = 1,000.00, so 687.71 goes to the loan and the balance becomes 199,312.29.
Why does most of my early payment go to interest?
Because interest is charged on what you still owe, and at the start you owe the most. On the example loan, 59.3% of the first payment is interest; from payment 43 onwards more of each payment goes to the principal than to interest.
How much do extra payments save?
Every extra amount goes straight to the principal, so later interest is charged on a smaller balance. Paying 200 extra each month on the example loan saves 18,230 of interest and clears it 2 years 4 months early. Check first whether your lender charges a prepayment fee.
Is it better to pay extra every month or once a year?
The same amount saves a little more when paid monthly, because it cuts the balance sooner: 200 a month saves 18,230, while 2,400 once a year (at the end of each loan year) saves 17,005. A one-off 10,000 in month 24 saves 11,151. Pick what fits your cash flow; the calculator shows each.
Can I use it for a mortgage, car loan or personal loan?
Yes, for any fixed-rate loan repaid in equal monthly payments. It shows principal and interest only: for a mortgage with property tax, insurance and PMI use the mortgage calculator, and for weekly or two-weekly payments or fees use the loan calculator.
