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Amortization Calculator

See exactly how any fixed-rate loan is paid off. Enter the amount, rate and term to get the monthly payment and a full month-by-month amortization schedule with a yearly summary. Add an extra monthly payment to see how much interest and time you save.

$
% / yr
$/ mo

Optional. Added to every payment and applied to principal.

Enter your values to see the result.
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How to use the Amortization Calculator

  1. Enter the loan amount and the annual interest rate.
  2. Set the term in years or months and the date of your first payment.
  3. Optionally add an extra monthly payment that goes straight to principal.
  4. Read the monthly payment, total interest and payoff date, plus the savings from extra payments.
  5. Scroll through the yearly summary and monthly schedule, and download either one as a CSV file.

How loan amortization works

Each month the lender charges interest on the balance you still owe, and the rest of your fixed payment pays down principal:

  • Payment M = P × r(1 + r)n ÷ ((1 + r)n − 1)
  • Interest this month = balance × r
  • Principal this month = M − interest (+ any extra payment)
  • New balance = balance − principal

Here P is the loan amount, r is the annual rate ÷ 12 ÷ 100 and n is the number of monthly payments. Because the balance falls every month, interest falls too and an ever larger share of the payment goes to principal.

Example: first months of a $250,000 loan at 6.5% for 30 years

MonthPaymentInterestPrincipalBalance
1$1,580.17$1,354.17$226.00$249,774.00
2$1,580.17$1,352.94$227.23$249,546.77
3$1,580.17$1,351.71$228.46$249,318.31

Over all 360 payments this loan costs about $318,861 in interest, more than the amount borrowed.

Effect of extra monthly payments

Same $250,000 loan at 6.5% for 30 years (regular payment $1,580.17):

Extra per monthTotal interestInterest savedPaid off in
$0$318,861$030 yr
$100$260,001$58,86025 yr 4 mo
$200$221,243$97,61822 yr 1 mo
$500$155,345$163,51616 yr 3 mo
$1,000$105,402$213,45911 yr 6 mo

Before paying extra, check that your loan has no prepayment penalty and that the lender applies extra money to principal.

Frequently asked questions

What is an amortization schedule?

It is a table that lists every payment on a loan and splits each one into interest and principal, along with the balance left after the payment. With a fixed-rate loan the payment stays the same, but the interest part shrinks and the principal part grows over time.

How is each monthly payment split between interest and principal?

Interest for the month is the current balance times the monthly rate (annual rate ÷ 12). The rest of the payment reduces the principal. For example, on a $250,000 loan at 6.5%, the first month's interest is $250,000 × 0.065 ÷ 12 = $1,354.17, so only $226.00 of the $1,580.17 payment goes to principal.

What formula does the calculator use?

The fixed payment is M = P × r(1+r)^n ÷ ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate and n is the number of payments. At a 0% rate the payment is simply P ÷ n.

How much do extra payments save?

Extra money paid toward principal reduces the balance that future interest is charged on. On a $250,000, 30-year loan at 6.5%, adding $200 a month cuts total interest from about $318,861 to about $221,243 and pays the loan off about 7 years and 11 months early.

Does it work for car loans and personal loans?

Yes. Any loan with a fixed rate and equal monthly payments amortizes the same way. Enter the term in months for car loans (for example 60 or 72 months).

Why is my lender's schedule slightly different?

Lenders round each payment to the cent, may calculate interest daily, and may count days between payments differently. Those details can shift totals by a few cents or dollars, but the overall schedule should match closely.

Is my data stored or uploaded?

No. The schedule is calculated in your browser. Your inputs are only remembered locally on your device so they are filled in next time.

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