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Loan Calculator

Monthly payments, total cost and full amortization schedule - free and private.

How Loan Calculator works

Loan Calculator computes your fixed monthly repayment, total amount repaid, and total interest cost from three inputs: the principal, the annual interest rate, and the loan term in months. It uses the standard fixed-rate annuity formula, the same arithmetic banks apply to level-payment loans, and every calculation runs locally in your browser: the amounts you enter are never sent to a server.

Expand the amortization schedule to see the principal-and-interest split for every individual payment. Early instalments go mostly to interest; later ones reduce the principal faster. This breakdown helps you understand how extra payments would shorten the term or reduce total interest. All figures are estimates based on a fixed rate and exclude origination fees, insurance, or any rate adjustments. Treat the output as a planning guide, not a binding offer or financial advice.

Written by Bastien Sulyan

How to use Loan Calculator, step by step

  1. Enter the loan amount (principal) in your currency.
  2. Enter the annual interest rate as a percentage (for example, 5.5 for 5.5%).
  3. Enter the loan term in months (for example, 360 for a 30-year mortgage).
  4. Read the monthly payment, total repaid, and total interest from the summary panel.
  5. Click Show amortization schedule to see the principal and interest split for each payment.

Common use cases

  • Comparing two mortgage offers side-by-side by running each set of figures separately to see which total interest cost is lower.
  • Estimating the monthly cost of a car loan before visiting a dealership, so you know your budget ceiling.
  • Checking how shortening a personal loan term from 5 years to 3 years changes the monthly payment and total interest.
  • Explaining to a family member how an amortization schedule works, using concrete numbers from a real loan.

Frequently asked questions

Does this calculator send my financial figures to any server?

No. The annuity formula runs entirely in your browser using JavaScript. Your loan amount, interest rate and term are never transmitted anywhere. The calculation happens locally, and the results exist only in your browser tab.

What formula does it use?

The monthly payment M = P * r * (1 + r)^n / ((1 + r)^n - 1), where P is the principal, r is the monthly interest rate (annual rate divided by 12), and n is the number of monthly payments. This is the standard fixed-rate annuity formula.

Is the monthly payment amount guaranteed or legally binding?

No. The result is a mathematical estimate based on the inputs you provide. It assumes a constant interest rate throughout the term and excludes origination fees, insurance, prepayment penalties and any variable-rate adjustments. Always refer to the official loan offer from your lender for the binding figures. This tool provides planning estimates only, not financial advice.

What is an amortization schedule and why does it matter?

An amortization schedule lists every payment in the loan term and shows how much of each payment reduces the principal versus how much goes to interest. In a typical mortgage, most early payments go to interest, with the principal share growing each month. Seeing this breakdown helps you gauge the real cost of the loan and the effect of overpayments.

Can I use it for a mortgage, a car loan, and a personal loan?

Yes. The annuity formula applies to any fixed-rate instalment loan. Enter the principal, annual rate and term in months for the loan type you are evaluating. For a 30-year mortgage, the term is 360; for a 5-year car loan, it is 60.

Does it work without an internet connection?

Yes. Once the page has loaded, the calculator runs without any network access. All computation is local JavaScript arithmetic, which is also why your financial figures stay on your device.

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