Amortization Schedule
Understand how an amortization schedule works and generate a full one with our mortgage calculator.
Generate a complete amortization schedule — annual and monthly breakdowns, a payoff chart, and support for extra payments — with our full calculator:
Open the Mortgage Calculator →What is an amortization schedule?
An amortization schedule is a complete table of every payment on a loan, showing how each installment is split between interest and principal until the balance reaches zero. It is most commonly used for mortgages, car loans and personal loans that are repaid in equal monthly installments over a fixed term.
Even though your monthly payment stays the same, the composition of that payment changes over time. Early on, most of each payment goes toward interest because the outstanding balance is large. As the balance shrinks, more of every payment goes toward principal — a process called amortization.
The amortization formula
The fixed monthly payment is calculated with the standard annuity formula:
M = P × r × (1 + r)ⁿ / ((1 + r)ⁿ − 1)
M = monthly payment
P = principal (loan amount)
r = monthly interest rate (annual rate ÷ 12)
n = total number of payments (years × 12)For each row of the schedule, the interest portion is the current balance × monthly rate, the principal portion is the payment minus that interest, and the new balance is the old balance minus the principal portion.
How a payment splits over time
Consider a $300,000 loan at 6% over 30 years (monthly payment ≈ $1,799). The table below shows how the interest/principal split shifts across the life of the loan:
| Payment | Toward interest | Toward principal |
|---|---|---|
| Month 1 | $1,500 (83%) | $299 (17%) |
| Year 10 | $1,275 (71%) | $524 (29%) |
| Year 20 | $830 (46%) | $969 (54%) |
| Final year | $70 (4%) | $1,729 (96%) |
Why extra payments save so much
Because early payments are mostly interest, any extra amount you pay goes straight to principal — which reduces the balance that all future interest is calculated on. Even one extra payment per year can shorten a 30-year mortgage by several years and save tens of thousands in interest. Our mortgage calculator lets you model extra payments and see the savings instantly.
This tool provides estimates for informational and educational purposes only and is not financial advice. Confirm exact figures with your lender.
Frequently asked questions
What is an amortization schedule?
It is a table showing every loan payment split into principal and interest, with the remaining balance, until the loan is fully paid off.
Why is early interest so high?
Interest is charged on the outstanding balance, which is largest at the start. So early payments are mostly interest, and later ones are mostly principal.
How do extra payments change the schedule?
Extra payments go straight to principal, reducing the balance that future interest is based on, which shortens the term and lowers total interest.
Where can I generate a full schedule?
Use the linked mortgage calculator, which produces a complete amortization table with annual and monthly views and supports extra payments.