How it works
An amortization schedule lists every payment on a fixed-rate loan and splits it into the part that pays interest and the part that reduces the balance.
Interest each month is the remaining balance times the monthly rate, so it is largest at the start. As the balance falls, more of the same payment goes to principal.
Switch to the yearly view for a compact summary, or pick a starting year to page through the monthly rows. Extra principal shows how prepaying changes the schedule.
Formula
Interest = balance × (rate ÷ 12); principal = payment − interest; new balance = balance − principal
Questions people ask
Why is so much of my early payment interest?
Interest is charged on the outstanding balance, which is highest at the start. On a 30-year mortgage at 6%, more than 80% of the first payment is interest.
How do extra payments change the schedule?
Extra principal lowers the balance immediately, so every later payment carries less interest and more principal. The loan ends earlier, but the required monthly payment stays the same.
Does amortization apply to credit cards?
Not in the same way. Credit cards have revolving balances and minimum payments that change each month, so they do not follow a fixed amortization schedule.