Credit Card Validator

Validate Credit Card Numbers Online — Free Luhn Checker

Check whether a card number is well-formed: the right length, a recognised card type, and a valid Luhn checksum. It's a fast way to catch typos and to test payment forms — without using a real card.

How to Validate a Card Number

Type or paste the number — spaces and dashes are fine. The tool identifies the card type (Visa, Mastercard, American Express, Discover, Diners Club, JCB, UnionPay, Maestro, or Mir), checks the length against what that network uses, runs the checksum, and shows the number neatly grouped. While you're still typing it tells you to keep going rather than flagging an error too early. Prefer not to type anything? Use the test-number buttons for Visa, Mastercard, Amex, Discover, JCB, and Diners.

How the Luhn Check Works

Nearly every card number ends in a check digit, calculated with the Luhn algorithm devised by IBM engineer Hans Peter Luhn in the 1950s. Starting from the last digit and moving left, every second digit is doubled (subtracting 9 from any result above 9), then everything is added up. If the total divides evenly by 10, the number passes. The check catches any single mistyped digit and most swapped neighbouring digits, which is why payment forms use it to spot typos instantly. Open See how the checksum works to watch the calculation digit by digit.

Passing the check only means the number is well-formed. It doesn't mean the card is real, active, or has funds, and this tool never asks for an expiry date or security code. Only a payment processor can confirm that a card is genuine.

Good Uses for This Tool

Testing checkout and billing forms with test numbers, checking a number you've typed before you submit it, teaching or learning how the Luhn algorithm works, and identifying which network a number belongs to.

Is It Actually Private?

Yes. Validation happens in your browser and nothing you type is sent anywhere. Even so, it's best to use the built-in test numbers rather than entering a real card number into any website you don't need to.