What this checks
Every payment card number ends in a check digit computed with the Luhn algorithm (ISO/IEC 7812). This tool verifies that checksum, the number length, and the network implied by the first digits. It is built for developers testing checkout forms and support teams validating typos.
What it does not check
Luhn validity does not mean a card is real, active or funded - only the issuing bank knows that. To see who issued a card and from which country, use the BIN checker with the first 6-8 digits only.
Test numbers
Standard test numbers that pass Luhn: 4111 1111 1111 1111 (Visa), 5555 5555 5555 4444 (Mastercard), 3782 822463 10005 (Amex). These are reserved for testing and cannot transact.
Frequently Asked Questions
What is a Luhn check?
The Luhn algorithm is the checksum every payment card number must pass: the last digit is computed from all the others. It catches typos, not fraud - a number that passes Luhn is well-formed, not necessarily real or active.
Is it safe to type a card number here?
The validation runs entirely in your browser with JavaScript. The number is never transmitted, logged or stored anywhere. You can verify this in your browser developer tools: no network request is made.
Does a valid Luhn check mean the card is real?
No. Luhn validity only means the digits are consistent. Whether the card exists, is active, or has funds can only be determined by the issuing bank during an actual authorization.