Amortization Schedule Calculator

When you take out a fixed-rate loan — whether for a home, car, or student expenses — each monthly payment is divided between paying interest on the outstanding balance and reducing the principal. An amortization schedule maps out this division for every payment over the life of the loan, giving you a clear picture of exactly where your money goes each month.

How Amortization Works

In a standard amortizing loan, your monthly payment stays the same throughout the loan term, but the composition changes dramatically over time. In the early years, most of each payment goes toward interest because the outstanding balance is large. As you pay down the principal, less interest accrues each month, so a larger portion of your fixed payment goes toward principal reduction. By the final years, almost all of each payment reduces the principal.

For example, on a $300,000 mortgage at 6.5% over 30 years, the first payment of $1,896 includes $1,625 in interest and only $271 in principal. By month 180 (halfway through), the split is roughly even. By the final payment, almost the entire amount goes to principal.

The Impact of Interest Rates

Interest rate differences that seem small can have an enormous impact over a long loan term. On a 30-year $300,000 mortgage, the difference between 6% and 7% is approximately $71,000 in total interest paid. Even a 0.25% rate reduction can save $15,000–$20,000 over the life of the loan. This is why refinancing when rates drop can be so beneficial.

The annual percentage rate (APR) includes fees and closing costs in addition to the interest rate, giving a more complete picture of borrowing costs. Always compare APRs, not just interest rates, when shopping for loans.

The Power of Extra Payments

Making extra payments toward principal is one of the most effective ways to reduce total interest and shorten your loan term. Because extra payments reduce the principal balance immediately, they also reduce the interest charged in every subsequent month. Adding just $100 per month to a $300,000 mortgage at 6.5% can save over $60,000 in interest and pay off the loan nearly 5 years earlier.

Extra payments are most effective early in the loan when the outstanding balance is largest. Some borrowers make biweekly payments instead of monthly ones, which results in 26 half-payments (equivalent to 13 full payments) per year instead of 12, effectively adding one extra payment annually.

Choosing Your Loan Term

The most common loan terms are 15 and 30 years for mortgages, and 3 to 7 years for auto loans. Shorter terms have higher monthly payments but dramatically lower total interest costs. A 15-year mortgage at the same rate as a 30-year mortgage typically costs less than half the total interest, though the monthly payment is about 40–50% higher.

The right term depends on your financial situation. A longer term provides lower monthly payments and more cash flow flexibility. A shorter term builds equity faster and costs less overall. Some borrowers choose a longer term for the lower required payment but make extra payments as if they had a shorter term, giving them flexibility to reduce payments if needed.

Reading Your Amortization Schedule

An amortization schedule shows you the payment number (or month), the payment amount, how much goes to principal, how much goes to interest, and the remaining balance after each payment. The yearly summary aggregates these figures by year for a higher-level view.

Key things to look for: the point where principal exceeds interest in each payment (the 'crossover point'), the total interest paid over the life of the loan, and how extra payments affect both the timeline and total cost. These insights help you make informed decisions about prepayment strategies and refinancing opportunities.