Credit Card Validator
Validate credit card numbers: Luhn algorithm, card type detection, formatting.
100% client-side: your files never leave your browser
The Luhn algorithm is a simple checksum formula used to validate identification numbers:
- Starting from the rightmost digit, double every second digit.
- If doubling results in a value greater than 9, subtract 9.
- Sum all digits together.
- If the total modulo 10 equals 0, the number is valid.