Amortization Calculator
See your monthly payment, total interest and a year-by-year amortization schedule — plus how extra payments cut your loan short.
Formula
About this calculator
Amortization is the process of paying off a loan with a series of equal, scheduled payments. Each payment is split into two parts: interest on the outstanding balance and principal that reduces what you owe. An amortization calculator shows both the single monthly payment you commit to and the full breakdown of how every dollar is applied over the life of the loan.
The monthly payment comes from the standard amortizing-loan formula, where M is the payment, P is the amount borrowed, r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments. Because interest is charged on the remaining balance, early payments are mostly interest and later payments are mostly principal — the schedule makes this shift visible month by month and year by year.
The most useful feature is the extra-payment field. Any amount you pay above the required payment goes straight to principal, so it stops accruing interest for the entire remaining term. Even a modest extra payment each month can shave years off a long loan and save thousands in interest; the calculator quantifies exactly how much time and money you save.
Example: a $250,000 loan at 6.5% over 30 years costs about $1,580 per month and roughly $319,000 in total interest. Adding just $200 a month pays the loan off almost 8 years early and saves nearly $98,000 in interest — the clearest illustration of why the amortization schedule, not just the payment, is worth studying.
Frequently asked questions
What is an amortization schedule?
It is a table listing every payment over the life of a loan, showing how much of each payment goes to interest, how much to principal, and the remaining balance afterward.
Why is so much of my early payment interest?
Interest is charged on the outstanding balance, which is largest at the start. As the balance falls, the interest portion shrinks and more of each fixed payment goes to principal.
How do extra payments help?
Extra payments apply entirely to principal, reducing the balance that future interest is calculated on. This shortens the term and lowers total interest without changing your required payment.
Does this work for any loan type?
Yes. Any fixed-rate, fully amortizing loan — mortgage, auto, personal or student — follows the same math, so you can use it for all of them.
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⚠️ Estimates assume a fixed rate and do not include lender fees, taxes or insurance. Confirm exact figures with your lender.