moneyWhat an amortization schedule shows
An amortization schedule lists every payment on a fixed-rate loan and splits it into interest and principal, with the balance left afterwards. Early payments are mostly interest because interest is charged on a large balance; as the balance falls, more of the same payment goes to principal. This calculator builds the full month-by-month schedule and totals each year.
How to use it
Enter the loan amount, interest rate, term in years and the month of your first payment. Switch between the yearly summary and every payment, and download the full schedule as a CSV file to open in a spreadsheet. The file is created in your browser.
Add an extra monthly principal payment to see how much sooner the loan is paid off and how much interest you avoid.
Assumptions
- Fixed rate, monthly compounding, payments at the end of each month, interest rounded to the cent.
- The regular payment is rounded to the nearest cent; the last payment is adjusted by a few cents so the balance ends at exactly zero.
- Extra payments go entirely to principal every month. Some lenders need you to label extra payments as principal-only. Taxes, insurance, fees and rate changes are not included.
Worked example
A $250,000 loan at 6.75% for 30 years has a payment of $1,621.50. The first payment is $1,406.25 interest and only $215.25 principal. In the first year you pay $16,793.57 in interest and reduce the balance to $247,335.57. Over the full term interest totals $333,734. Adding $200 a month in extra principal pays the loan off in 22 yr and saves $103,605 in interest.
Frequently asked questions
Why does so much of my early payment go to interest?
Each month’s interest is the rate times the remaining balance. At the start the balance is largest, so interest takes most of the payment. Principal paid grows every month as the balance shrinks.
How do extra payments change the schedule?
Extra principal lowers the balance immediately, so every later month accrues less interest. The required payment stays the same but the loan ends earlier. The schedule here shows the shorter payoff and interest saved.
Can I open the schedule in Excel or Google Sheets?
Yes. Use Export CSV to download the payment number, month, payment, principal, interest and remaining balance for every payment. The file is generated on your device and is not uploaded.
Will this match my lender’s schedule exactly?
It should be close for a standard fixed-rate loan, but lenders may count interest daily, set a different first-payment date or round differently. Your servicer’s statement is the official record.