Loan Payment Calculator

Calculate monthly payment, total interest, and total cost from principal, APR, and term. Optional extra payment shows how fast you can crush the balance.

How to Use

  1. Enter the loan amount (principal).
  2. Enter APR (annual interest rate).
  3. Choose a term (years or months).
  4. Optional: add an extra monthly payment to see payoff acceleration.
Inputs
Results update instantly. Share links are generated only by the Share button.
Amount borrowed before interest. Example: 25,000
APR example: 7.5% (or 0.075 in decimal mode)
Common terms: 36, 48, 60, 72 months or 15/30 years
Extra payment reduces interest and shortens payoff time.
Show Work (step-by-step)
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Work uses standard amortized loan math (fixed-rate). Values are shown in monthly terms for clarity.
Amortization Preview
Preview shows early payments to help you understand interest vs principal.
Enter inputs to generate a preview.

Loan Payment Formulas

For a fixed-rate loan, the monthly payment (PMT) is:

PMT = P × r × (1 + r)^n / ((1 + r)^n − 1)

  • P = principal (loan amount)
  • r = monthly interest rate = APR ÷ 12
  • n = number of monthly payments
If APR is 0%, payment is simply P ÷ n.

FAQ

Does this include taxes or insurance?

This tool calculates the loan itself (principal + interest). You can add lender fees into principal if you want, but taxes/insurance are usually separate.

Why does extra payment save so much interest?

Interest is computed on the remaining balance. Paying down principal earlier reduces the balance sooner, which reduces future interest.

What if my rate changes?

This is for fixed-rate loans. Adjustable-rate loans need a schedule of future rates to model accurately.

Tool Info

Last updated:

Updates may include better amortization views, edge-case handling, and additional payment options.