Amortization Schedule Calculator

Amortization schedule calculator for loans and monthly payments

An amortization schedule shows how a loan balance changes over time when you make regular payments. Each payment is split into two parts: interest (the cost of borrowing) and principal (the amount that actually reduces the balance). In the early months, interest usually takes a larger share of each payment because the balance is still high. Over time, as the balance shrinks, the interest portion drops and more of each payment goes toward principal.

This calculator creates a month-by-month amortization table from three core inputs: loan amount, interest rate (APR), and loan term in years. It also estimates the fixed monthly payment for a standard fully amortizing loan. If you add an optional extra payment per month, the calculator re-runs the schedule using the same interest rate but a faster payoff. That lets you see two practical things most people care about: how much interest you can save and how many months you can cut off the loan.

To use it, enter your loan amount (the principal), your annual interest rate (APR), and the loan term. If you do not know the exact APR, use the best estimate you have from a quote or statement. Then, optionally enter an extra monthly payment amount. An extra payment does not change the interest rate. It simply reduces the balance faster, which reduces future interest because interest is calculated on the remaining balance each month. The results include the estimated monthly payment, totals over the life of the loan, and (if enabled) a full amortization table showing every month’s payment split and remaining balance.

Assumptions and how to use this calculator

• Payments are calculated monthly using a standard fixed-rate amortization formula (APR divided by 12).
• If the interest rate is 0%, the payment is principal divided evenly across months (no interest added).
• Extra monthly payments (if provided) are applied directly to principal after the scheduled payment is applied.
• The final payment is adjusted automatically if the remaining balance is smaller than the scheduled principal portion.
• Results are estimates and may differ from your lender due to rounding rules, fees, insurance, or payment timing specifics.

Common questions

What is an amortization schedule and why does it matter?

An amortization schedule is a detailed table that shows each payment date (or payment number), how much of that payment is interest, how much is principal, and what balance remains afterward. It matters because it makes the cost of borrowing visible. You can see how much interest you pay early on, how quickly (or slowly) the balance falls, and what happens if you make extra payments.

Why is so much of my payment interest at the beginning?

Interest is calculated on the outstanding balance. At the start of a loan, the balance is at its highest, so the interest charge for that month is also at its highest. Your payment is fixed, so the principal portion starts smaller. As the balance decreases, the interest portion decreases too, leaving more of the fixed payment to reduce principal.

How do extra payments reduce total interest so much?

Extra payments reduce the balance sooner. Since future interest is calculated on the balance, a lower balance means lower interest every month after that. The effect compounds across the remaining term. Even a small extra payment can shorten the loan and remove many months of future interest charges.

Does an extra payment change my required monthly payment?

No. Your required scheduled payment is set by the original loan terms. Extra payments are voluntary amounts you add on top. Some lenders apply extras to principal by default, while others require you to specify principal-only. Always verify how your lender applies extra payments to avoid surprises.

When will my results differ from my lender’s statement?

Differences usually come from timing and fees. Lenders may calculate interest daily, round each month differently, or include additional charges like account fees, insurance, or taxes. If you want the closest match, use the exact APR, confirm whether interest is daily or monthly, and treat this schedule as a planning estimate rather than a legal payoff quote.