Credit Card Validator - Validate Card Numbers with Luhn Algorithm
Validate credit card numbers using the Luhn algorithm and detect card type (Visa, Mastercard, Amex)
Generators
Tool
Generate Test Numbers
These are test numbers valid per Luhn algorithm only — not real cards.
How to Use
1Enter a credit card number in the input field
2The tool automatically formats the number as you type
3View the validation result (valid or invalid)
4See the detected card type (Visa, Mastercard, American Express, etc.)
5Use 'Generate Test Number' to get valid test card numbers for development
6Note: This tool only validates format, not actual card existence
Frequently Asked Questions
The Luhn algorithm (also called Mod 10) is a checksum formula used to validate credit card numbers. It works by doubling every second digit from right, summing all digits, and checking if the total is divisible by 10. Valid card numbers always pass this check.
This tool runs entirely in your browser and does not send data to any server. However, for security best practices, we recommend using test card numbers for development and testing purposes only.
Card types are identified by their prefix digits: Visa starts with 4, Mastercard starts with 51-55 or 2221-2720, American Express starts with 34 or 37, Discover starts with 6011 or 65.
Generated test card numbers are valid according to the Luhn algorithm and are useful for development, testing payment integrations, and validating form inputs. They don't correspond to real accounts.