Amortization Calculator

Understanding Loan Amortization: A Complete Guide

An amortization schedule is one of the most powerful tools for understanding your loan. It reveals exactly where every dollar of your payment goes — and how extra payments can dramatically change the outcome. Whether you have a mortgage, auto loan, or personal loan, this guide explains how amortization works and how to use it to your advantage.

How Amortization Works

With an amortized loan, each monthly payment is the same amount, but the split between principal and interest changes over time. In the early years, most of your payment goes toward interest because the outstanding balance is large. As you pay down the principal, less interest accrues, and more of each payment reduces your balance. This calculator shows you that shift month by month.

The Power of Extra Payments

Extra payments go directly toward reducing your principal balance. Since interest is calculated on the remaining balance, every extra dollar you pay today saves you interest for the remaining life of the loan. On a $250,000 mortgage at 6.5%, an extra $200/month saves over $70,000 in interest and pays off the loan nearly 7 years early.

Strategies for Extra Payments

• Bi-weekly payments: Pay half your monthly payment every two weeks — you'll make 26 half-payments (13 full payments) per year instead of 12
• Round up: Round your payment up to the next $100 for painless extra principal reduction
• Annual lump sum: Apply your tax refund or bonus as a one-time extra payment
• Dollar-a-month: Add $1 more to your extra payment each month — barely noticeable but adds up significantly

When NOT to Make Extra Payments

Before aggressively paying down debt, consider: Does your loan have a prepayment penalty? Could the money earn more invested elsewhere? Do you have an emergency fund? If your loan rate is 4% but the stock market averages 10%, investing the extra might build more wealth. Use our compound interest calculator to compare.

Amortization vs. Other Loan Types

Not all loans amortize. Interest-only loans require you to pay only interest for a period, then either pay off the principal or start amortizing. Balloon loans have small payments with a large lump sum at the end. Standard amortization — used for most mortgages and auto loans — is the most predictable and transparent structure.