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Loan & Amortization Calculator

For any fixed-rate installment loan — car, personal, student or business. See the monthly payment, the total interest, and what happens if you pay a little extra each month.

Result

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Show full amortization schedule (by month)

For information only. Results are estimates based on the numbers you enter and the formula shown below. They are not financial, tax, legal or investment advice and do not replace a qualified professional or the official figures from your lender, employer or provider.

How to use this calculator

  1. Enter the amount you borrow and the yearly interest rate.
  2. Enter the term in years, and add months if the term is not a whole number of years (for example 5 years + 6 months).
  3. Optionally enter an extra monthly payment to see the interest and months it saves.
  4. Open the schedule to see every payment split into principal and interest.

The formula

Payment = P × r × (1 + r)^n ÷ ((1 + r)^n − 1) Each month: interest = balance × r principal = payment − interest (+ extra) balance = balance − principal

P is the amount borrowed, r is the yearly rate divided by 12, and n is the number of monthly payments. If the rate is 0%, the payment is simply P ÷ n. Interest is rounded to the smallest currency unit each month, and the last payment is adjusted so the balance ends at exactly zero.

Worked example

$20,000 car loan at 7% for 5 years

  1. r = 7% ÷ 12 ≈ 0.0058333, n = 60.
  2. (1 + r)^60 ≈ 1.417625.
  3. Payment = 20,000 × 0.0058333 × 1.417625 ÷ 0.417625 ≈ $396.02.
  4. First month: interest = 20,000 × 0.0058333 = $116.67, so $279.35 goes to principal.

Total interest over five years is about $3,761. Adding $100 a month pays the loan off months earlier — try it above.

Frequently asked questions

What is an amortization schedule?

A table that shows each payment split into interest and principal, and the balance left afterward. It shows how a fixed payment shifts from mostly interest to mostly principal over time.

Do extra payments really save money?

Usually yes. Extra money reduces the principal, so less interest is charged in every later month. Check first that your loan has no prepayment penalty and that the lender applies extra payments to principal.

Is a longer term better because the payment is lower?

A longer term lowers the monthly payment but increases the total interest you pay, as the CFPB notes for auto loans.

Why is my lender's payment slightly different?

Lenders may count days differently, round at different steps, or add fees and insurance to the payment. Your loan disclosure shows the official figures.

Does this work for interest-only or variable-rate loans?

No. It assumes a fixed rate and equal monthly payments that fully repay the loan.

Sources

Last reviewed November 6, 2026. Calculations run in your browser; nothing you type is sent to us. Spotted a mistake? Tell us.