Credit Card Validator

Credit Card Validator

Check whether a card number is correctly formed using the Luhn checksum and detect its brand. This tool never charges, stores, or verifies real cards.

Common public test numbers: Visa 4242 4242 4242 4242 · Mastercard 5555 5555 5555 4444 · Amex 3782 822463 10005 · Discover 6011 1111 1111 1117. Always use test numbers, never a real card, on any demo or practice page.

A Credit Card Validator checks whether a card number is written in a correct, plausible format before a payment system wastes time on it. It uses the Luhn checksum, a simple mathematical test built into every real card number, which catches most single-digit mistakes and swapped digits instantly. It also recognises the brand, Visa, Mastercard, American Express, or Discover, from the opening digits and length. Developers use a tool like this while building checkout forms, and shoppers use it to spot a typing error when a genuine payment keeps failing at the first step.

Please read this limit carefully, because it matters. Passing this check only means the number follows the correct pattern and its checksum adds up. It does not prove the card exists, belongs to you, has funds, or will be accepted, and this page has no connection to any bank or payment network.

How to use

  1. Type or paste a number and it will be spaced automatically in the standard grouping.
  2. Read the detected brand and digit count to confirm they match the card in front of you.
  3. Check the Luhn result: PASS means correctly formed, FAIL means a digit is wrong somewhere.
  4. If a real payment fails despite a PASS here, the problem lies with the bank, funds, or card status, not the format.
  5. Use only the published test numbers when practising, building, or demonstrating a checkout.

Frequently asked questions

What is the Luhn checksum in simple words?

It is an arithmetic pattern hidden in the number itself. Starting from the right, you double every second digit, add everything together in a set way, and a genuine number always ends with a total divisible by ten. It was designed to catch typing mistakes quickly, not to prove a card is real or funded, and every card network uses it.

Why does a made-up number sometimes pass?

Because the checksum is only arithmetic, about one in ten random numbers will pass it by chance, and test numbers are deliberately built to pass. A pass is the first filter a checkout applies, after which the bank checks the account itself. This is exactly why a PASS here must never be treated as proof of a working card.

Is it safe to type my real card number here?

The calculation is local and nothing is transmitted, but the safe habit is to never type a full real card number into any web tool, including this one. Use the public test numbers for checking the tool, and if you must diagnose a failing payment, compare digits visually against your card instead of pasting the number into websites.

Why are the test numbers public?

Payment companies publish them so developers can test checkout systems in a sandbox where no money moves. In a real live checkout those numbers are declined like any other invalid account. They are safe to share precisely because they are not connected to any person's money or credit.