For Testing Only - Never Use Real Card Numbers
This tool is designed for developers and testers to validate card number formats. Never enter your real credit card information. Use official test numbers from payment processors like Stripe or PayPal for development purposes.
Credit Card Validator
Validate credit card numbers using the Luhn algorithm and detect card types. Perfect for testing payment integrations and understanding card number validation.
Enter digits only (spaces are allowed and will be removed automatically)
Enter a credit card number above to validate it
Supported Card Types
Visa
Starts with 4, 13 or 16 digits
Example: 4532015112830366
Mastercard
51-55 or 2221-2720, 16 digits
Example: 5425233430109903
American Express
Starts with 34 or 37, 15 digits
Example: 378282246310005
Discover
6011, 622126-622925, 644-649, 65, 16 digits
Example: 6011111111111117
Frequently Asked Questions
What is the Luhn algorithm?
The Luhn algorithm (also known as modulus 10 or mod 10 algorithm) is a checksum formula used to validate credit card numbers. It works by doubling every other digit from right to left, subtracting 9 if the result is greater than 9, and checking if the sum of all digits is divisible by 10. This simple but effective algorithm helps catch common errors in card number entry.
Is it safe to enter my real credit card number?
No! This tool is for testing and educational purposes only. Never enter your real credit card number into any online tool unless it's an official payment gateway (like your bank or a trusted merchant). For development and testing, use official test card numbers provided by payment processors like Stripe, PayPal, or your payment gateway provider.
What card types can this tool detect?
This tool can detect major card types including Visa (starts with 4), Mastercard (51-55 or 2221-2720), American Express (34 or 37), and Discover (6011, 622126-622925, 644-649, 65). Detection is based on the IIN (Issuer Identification Number) patterns defined by the card networks.
What are valid test credit card numbers?
Common test numbers that pass Luhn validation include: Visa: 4532015112830366, Mastercard: 5425233430109903, American Express: 378282246310005, Discover: 6011111111111117. These numbers pass the mathematical check but are not real, active cards. Payment processors provide their own test numbers for integration testing.
Why is my card number showing as invalid?
A card number may be invalid if it fails the Luhn algorithm check (the sum of processed digits is not divisible by 10), has incorrect length (cards are typically 13-19 digits), or doesn't match known card type patterns. This tool only validates the mathematical checksum and format, not whether the card actually exists or is active.
Can this tool be used for fraud?
No. This tool only validates the mathematical checksum of a number - it cannot generate valid card numbers, verify expiration dates, CVV codes, cardholder names, billing addresses, or determine if a card is active or has available credit. It's purely an educational tool for understanding card validation and testing payment system integrations in a safe development environment.