Amortization Calculator
Build the complete amortization schedule for a loan: every monthly payment split into principal and interest, year by year. Add an extra monthly payment to see how much sooner the loan is cleared and how much interest it saves.
Set an extra monthly payment to see how much sooner the loan could be paid off.
Formula and calculation
Worked example
A $200,000 loan at 6.5% over 30 years has a scheduled payment of $1,264.14. Paying $200 extra every month pays it off 110 months early and saves $90,076.78 — the total interest drops from $255,088.98 to $165,012.20.
How the extra payment changes the schedule
The scheduled payment never changes when you pay extra — the extra amount goes straight onto the balance, so next month's interest is charged on a smaller number. That compounds: every extra dollar removes all the interest it would have accrued for the remaining term, which is why even modest extras cut years off a long loan. The monthly table on this page shows the effect month by month, and the final payment comes out smaller than usual because the balance runs out mid-schedule. The yearly table is the shortcut view: watch the balance column shrink faster year by year.
What the results mean
- Monthly payment
- The scheduled payment under the amortization formula — the same every month, before any extra you add. It covers principal and interest for the loan itself.
- Interest saved
- How much less interest you pay because of the extra monthly payment. It is 0 when no extra payment is set.
- Total interest
- Interest over the life of the loan as actually scheduled, including the effect of your extra payments.
- Interest with no extra payments
- Interest over the full term with no extra payments — the number your extra payment is cutting into.
- Months saved
- How many months earlier the loan is paid off thanks to the extra payment. Divide by 12 for years.
- Total of all payments
- Everything you hand the lender over the life of the loan: principal plus interest, nothing else.
- Payoff date
- The month of the final payment under this schedule, counted from the first payment date.
Frequently asked questions
How does an amortization schedule work?
Each monthly payment is applied first to the interest due on the remaining balance, and the rest reduces the balance. Early on, almost everything goes to interest; in the final years almost everything goes to principal. The schedule shows this split for every payment.
How much do extra payments save?
On a $200,000 loan at 6.5% over 30 years, an extra $200 a month finishes the loan 110 months (over 9 years) early and saves about $90,100 of interest. On a $300,000 loan, $300 a month saves roughly $135,100 and 9 years.
Do extra payments go to principal or interest?
To principal. Your scheduled payment already covers that month's interest, so any amount on top of it reduces the balance itself — and less balance means less interest next month and every month after.
Is one lump sum better than small monthly extras?
For the same total dollars, money paid earlier saves more interest, so a lump sum in month one beats the same amount trickled over a year. Monthly extras are easier to budget and often work out best in practice, because they happen automatically.
Does this calculator handle interest-only or balloon loans?
No — it models fully amortizing fixed-rate loans, where each payment covers interest plus principal and the balance reaches zero at the end. Interest-only periods and balloon payments need a different schedule.