Mortgage Amortization Schedule Calculator

Full amortization schedule

Each row shows how the payment splits between principal and interest, and what balance remains after.

What is amortization?

Amortization is the process of paying down a loan with fixed payments where each payment is a blend of interest on the outstanding balance and principal reduction. Early in the loan almost all of the payment is interest because the balance is high; the principal portion grows every month and finally surpasses interest somewhere around year 18 of a 30-year mortgage. The total payment never changes, but the split inside each payment shifts continuously. Most online calculators give you only the headline monthly figure; a full amortization schedule shows every period in the loan, which is essential for understanding how a single extra payment can shave years off the loan or for evaluating refinance break-evens.

How to use the calculator

1. Enter the loan principal — the amount actually borrowed (price minus down payment).
2. Enter the annual interest rate as listed on your loan estimate (APR is fine).
3. Set the term in years (usually 15 or 30).
4. The schedule appears below. Use the toggle to switch between monthly (360 rows for 30 years) or yearly totals.
5. Scroll the table to see exactly when interest stops dominating the payment.

How the math works

The fixed payment is the standard amortization formula. Each period’s interest equals last period’s balance times the monthly rate. Principal is whatever remains of the payment.

Payment = P × r(1+r)ⁿ / ((1+r)ⁿ − 1)

Interest_k = Balance_k−1 × r

Principal_k = Payment − Interest_k

Principal vs. interest by year

Approximate split of a typical 30-year loan at 6.5%.

Real numbers depend on the rate. Lower rates flip the principal majority earlier.

Frequently asked questions