See your full loan amortization schedule, total interest, and how extra payments shorten your payoff time.
Rates as of Q2 2025 (example)
| Period | Date | Payment | Principal | Interest | Balance |
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An amortization calculator shows exactly how a loan is paid off over time. For any fixed-rate loan — a mortgage, auto loan, or personal loan — it breaks each payment into the portion that goes toward interest and the portion that reduces your principal balance, and shows how that split changes month by month until the loan reaches zero.
Each monthly payment is calculated using the standard amortization formula, then split between interest and principal:
Formula: M = P × [r(1+r)n] / [(1+r)n − 1], where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (loan term in years × 12). Each month, the interest portion is the remaining balance multiplied by r, and the rest of the payment reduces the principal.
Example: On a $250,000 loan over 30 years at a 6.5% interest rate (example rate — enter your actual rate), the monthly payment is roughly $1,580. In the first month, around $1,354 goes to interest and only $226 reduces the principal — but that split shifts steadily toward principal as the loan matures. (Note: all figures in this example are for illustration purposes only and do not represent actual rates or market conditions.)
Most US mortgages, auto loans, and personal loans use this same fixed-payment amortization structure, where the total payment stays constant but the interest-to-principal split changes over time. Early in the loan, most of each payment goes toward interest — which is why extra payments made early have the biggest impact on total interest paid. Lenders are required to disclose the amortization schedule and total interest under federal Truth in Lending rules, so you can always compare this calculator's figures against your loan documents.
It shows, for every payment over the life of the loan, how much goes toward interest and how much reduces your principal balance, along with the remaining balance after each payment.
Interest is calculated on the remaining loan balance, which is highest at the start of the loan. As the balance shrinks with each payment, less interest accrues and more of each payment goes toward principal.
Yes — the amortization formula applies to any fixed-rate, fixed-term loan, including auto loans and personal loans, as long as you enter the correct loan amount, rate, and term.
It depends on the loan size, rate, and term, but extra payments made early in the loan can save thousands of dollars in interest and shave years off the payoff time, since they reduce the balance that future interest is calculated on.
No — the default rate is an example only. Always use the actual interest rate from your loan agreement or lender quote, since rates vary by lender, loan type, and your credit profile.
Yes — simply re-enter your new loan amount, interest rate, and term as if it were a new loan, and the calculator will generate a fresh amortization schedule based on those numbers.
Disclaimer: The information, rates, and figures provided on this page are for educational and illustrative purposes only. All rates and examples shown are sample values and do not reflect current or actual market rates. Financial rules and regulations change frequently. Always consult a qualified financial advisor, tax professional, or lender before making any financial decisions.