An amortization calculator shows how each loan payment is split between interest and principal over time. Early payments are mostly interest; later payments are mostly principal. The amortization schedule lists the payment, interest, principal, and remaining balance for every period.
How an amortization schedule works
Each period, interest is charged on the remaining balance and the rest of the fixed payment reduces the principal. As the balance falls, the interest portion shrinks and the principal portion grows, until the loan reaches zero at the end of the term.
Using extra payments
Any amount paid above the scheduled payment goes straight to principal, which lowers future interest and shortens the term. The schedule below updates to reflect extra payments so you can see the impact period by period.