Amortization calculator and schedule

On a fixed-rate mortgage the payment stays the same, but what it pays for changes every month. Early on, most of it is interest. Enter your loan amount, rate, and term to see the full schedule. Every box starts blank.

Enter your loan to see the schedule

Loan amount The amount borrowed, not the price of the home.

Interest rate (%) The annual rate a lender quoted you. This site does not supply rates. Up to 3 decimal places.

Loan termFixed-rate term.30 years25 years20 years15 years10 years

Show the scheduleClear

Why early payments are mostly interest

Each month, interest is charged on the balance you still owe: the balance times the annual rate, divided by 12. The rest of the fixed payment goes to principal and lowers the balance.

1. At the start, the balance is at its largest, so the interest part of the payment is at its largest too, and only a small slice is left for principal.
2. Each payment lowers the balance a little, so next month’s interest is a little smaller and the principal part a little bigger.
3. The shift speeds up over time. Somewhere in the loan, principal becomes the larger part of each payment; on longer terms and higher rates that happens later. The calculator shows the payment where it happens for your numbers.
4. By the end, almost the whole payment is principal, and the last payment brings the balance to zero.

That is why paying extra early has an outsized effect: every dollar of principal you pay ahead of schedule stops being charged interest for all the months that are left. See the extra payments calculator to try it.

How the calculator works

• Monthly principal and interest uses the standard formula: payment = loan × r ÷ (1 − (1 + r)⁻ⁿ), where r is the annual rate ÷ 12 and n is the number of monthly payments. The formula is explained on How a mortgage payment works.
• Each month: interest = balance × r, rounded to the cent; principal = payment − interest; new balance = old balance − principal. The last payment is adjusted so the balance ends at exactly zero.
• The yearly summary adds up each loan year (payments 1 to 12, 13 to 24, and so on), not calendar years.
• It shows principal and interest only. Your actual monthly payment may also include property taxes, homeowners insurance, and mortgage insurance; the payment calculator adds those.
• It assumes a fixed rate for the whole term. An adjustable-rate loan’s schedule changes when the rate does; see ARMs: the worst case under the caps.

What this leaves out: payment dates and day counts, late or missed payments, escrow, and fees. Your servicer’s schedule can differ by a few cents. It is education, not a quote.

Guidelines change; confirm with a licensed lender.