Mortgage Amortization Schedule Calculator

An amortization schedule shows how each monthly payment is split between interest and principal. The monthly payment is fixed at M = P[r(1+r)^n] / [(1+r)^n − 1]. Each month, the interest portion = remaining balance × monthly rate, and the principal portion = M − interest. Early in the loan, most of the payment goes to interest. For a $300,000 loan at 6.5% over 30 years (M = $1,896), the first payment splits into $1,625 interest and only $271 principal. By payment 180 (halfway), it shifts to $1,098 interest and $798 principal. The final payment is nearly all principal.

Understanding your amortization schedule helps you make informed decisions about extra payments. Even small additional payments toward principal in the early years can save tens of thousands in interest and shorten the loan by years. For example, adding just $200/month to a $300,000 loan at 6.5% over 30 years saves approximately $96,000 in interest and pays off the loan nearly 7 years early.