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Utilities

Credit Card Validator Documentation

Use the free Credit Card Validator →

Check a card number's Luhn checksum and identify its likely card network from the number pattern.

What does it do?

Check a card number's Luhn checksum and identify its likely card network from the number pattern.

How does it work?

SiteIndex runs the Luhn checksum algorithm against the digits you enter and matches the leading digits and length against known card network patterns.

When to use it
  • Verify a test card number passes the Luhn checksum before using it in a sandbox.
  • Confirm which network a card number pattern likely belongs to.
  • Catch a mistyped card number during manual data entry.
Inputs and outputs
Input
Text, files, or values entered in the browser, depending on the tool.
Output
A result shown in the browser that can be reviewed or copied where supported.
Limitations
  • No bank is contacted. A passing checksum cannot establish issuance, ownership, available funds, expiry, or payment authorization.
  • Non-digit characters are stripped, so inspect the digit count as well as the checksum.
Privacy and data handling

Inputs for this browser-side tool are processed locally and are not sent to SiteIndex. Normal page analytics may still be collected as described in the Privacy Policy. Read the Privacy Policy.

How to use it

  1. Use a documented synthetic test number, not a real card.
  2. Read the Luhn checksum, digit count, and likely network.
  3. Test any payment integration through the payment processor's authorized sandbox instead.

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