Amortization Calculator: Extra Payments & One-Time Payments

How to use

Calculate your amortization schedule and see the impact of extra payments.

1. Enter loan details

Input the loan amount, annual interest rate, and loan term in years.

2. Set the start date

Choose the month and year when your first payment is due.

3. Add extra recurring payments

Enter any extra amount you plan to pay each month or each year to pay down principal faster.

4. Add one-time payments (optional)

Use the repeating rows to enter lump-sum payments and the month number in which they will be applied.

5. Review results

See your payoff date, interest saved, and time saved compared to the original schedule.

FAQs

How does an extra monthly payment reduce my loan?

Any extra amount paid above your regular monthly payment goes directly toward principal, which reduces the balance on which interest is charged. This accelerates payoff and saves interest.

What is a one-time extra payment?

A one-time payment is a lump sum applied to the loan balance in a specific month (e.g., month 12 for a year-end bonus). Enter the month number and amount in the one-time payments section.

How is the payoff date calculated?

The calculator simulates month-by-month payments including all extra amounts and determines the month in which the balance reaches zero, then converts that count into a calendar date.

Does an extra yearly payment get added in a specific month?

Yes. The extra yearly payment is applied every 12th month of the loan (i.e., each December of the loan year). You can also model a specific month using the one-time payments feature.