Credit Card Validator (Luhn Algorithm)
Validate credit card numbers using the Luhn algorithm and detect the card network. Runs entirely in your browser — no data is sent anywhere.
🔒 Privacy: all validation runs locally in your browser. No data is transmitted.
The Luhn algorithm (also known as the "modulus 10" algorithm) is a simple checksum formula used to validate credit card numbers, IMEI numbers, and other identification numbers. It works by doubling every second digit from the right, subtracting 9 from any result over 9, and checking that the total sum is divisible by 10. Card network detection is based on IIN (Issuer Identification Number) prefixes. Note that passing the Luhn check only means the number is structurally valid — it does not verify that the card account exists or has funds.
Frequently Asked Questions
- Luhn (mod-10) is a checksum formula that validates the last digit of credit card numbers. It catches most transcription errors but is not a security mechanism.