CalcMyFin

Loans & Debt

Loan Payment Calculator

Work out the monthly payment on any fixed-rate loan, whether personal, student or business, and see the total interest you'll pay. Add an extra monthly amount to see how much faster you'd be debt-free.

  • Free, no sign-up
  • Private: runs in your browser
  • Updated September 2026

Inputs

$
Principal borrowed before interest.
%
yr
$
Optional amount added to the standard payment.

How to use the loan payment calculator

  1. Enter the amount you plan to borrow.
  2. Add the annual interest rate (APR) and the loan term in years.
  3. Optionally add an extra monthly payment to see its effect on payoff time and interest.

How it's calculated

The required payment uses the standard amortization formula M = P × r(1 + r)n ÷ [(1 + r)n − 1], where P is the amount borrowed, r is the monthly rate and n the number of payments. The calculator then simulates each month (interest first, then principal) to find the payoff date and total interest, including any extra payment you add.

Example

Borrowing $20,000 at 9% for 5 years costs $415.17 a month and about $4,910 in total interest.

Tips

  • Extra payments go straight to principal, so every extra dollar reduces future interest.
  • Check whether your lender charges prepayment penalties before paying early.
  • A shorter term raises the payment but usually cuts total interest dramatically.
  • Compare offers by APR, which includes most fees, rather than by the interest rate alone.

Frequently asked questions

How is a loan payment calculated?
Each payment covers that month's interest (balance × monthly rate) and the rest reduces the principal. Early payments are mostly interest, and later payments are mostly principal. The formula above finds the single fixed payment that brings the balance to zero by the end of the term.
How much does an extra payment save?
It depends on the rate and how early you start, but extra payments made early in a loan save the most, because they remove principal that would otherwise collect interest for years. Enter an amount above to see your exact savings in time and interest.
What's the difference between APR and interest rate?
The interest rate is the cost of borrowing the principal. APR also includes certain fees, such as origination fees, expressed as a yearly rate, which makes it better for comparing loan offers.
Can I use this for a car loan?
Yes, but our auto loan calculator also handles trade-ins, sales tax and dealer fees.
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Sources

This calculator provides educational estimates only and is not financial, tax, legal or investment advice. Results depend on the assumptions you enter; actual terms from lenders, insurers and tax authorities may differ.