Loan Calculator

Calculate the monthly payment, total interest, and payoff time for any fixed-rate loan, and see how extra payments save you money. Runs entirely in your browser.

Monthly payment

-

Total interest-
Total paid-
Payoff time-

Show the math

The monthly payment uses the amortization formula:

M = P · r(1 + r)n / ((1 + r)n − 1)

P = loan amount · r = annual rate ÷ 12 · n = number of monthly payments. Total interest is the sum of every payment minus the original loan. Extra payments go entirely to principal, so the balance (and the interest that builds on it) falls faster.

What this does

A loan calculator finds the monthly payment, total interest, and payoff time for any fixed-rate loan. Enter the amount, interest rate, and term, and it returns the payment and shows how extra payments save you money.

How to use it

  1. Enter the loan amount and interest rate.
  2. Choose the loan term in months or years.
  3. Optionally add an extra monthly payment.
  4. Read your monthly payment, total interest, and payoff time.

How it works

The payment uses the amortization formula M = P·r(1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly rate, and n is the number of months. With a 0% rate it is simply the amount divided by the number of months.

Understanding your result

A longer term lowers the monthly payment but raises total interest. Any extra payment goes straight to principal, shortening the term and cutting interest, the tool shows both the months and interest saved.

Example

A $20,000 loan at 7% over 5 years is about $396 a month and roughly $3,761 in total interest. Adding $100 a month clears it about 14 months early.

Sources & methodology

Last updated .

Frequently asked questions

How is the monthly payment worked out?

It uses the standard amortization formula M = P·r(1+r)ⁿ / ((1+r)ⁿ − 1), where P is the loan amount, r is the monthly rate (annual rate ÷ 12), and n is the number of months. With a 0% rate it is simply the loan divided by the number of months.

What does an extra monthly payment do?

Any amount above the scheduled payment goes straight to principal, so the balance falls faster. That shortens the term and cuts the total interest, this tool shows both the months saved and the interest saved.

Is the interest fixed?

This calculator assumes a fixed rate for the whole term. Variable-rate loans can change over time, so treat the result as an estimate for a comparable fixed loan.

Do you store my numbers?

No. Everything is calculated locally in your browser, nothing you enter is uploaded or saved.