Credit Card Validator
Validate credit card numbers using the Luhn algorithm. Check Visa, Mastercard, American Express, and other card types instantly.
Enter Credit Card Number
Enter 13-19 digits. Spaces are automatically formatted.
Test Card Numbers (For Testing Only)
- Visa: 4532 1488 0343 6467
- Mastercard: 5425 2334 3010 9903
- American Express: 3782 822463 10005
- Discover: 6011 1111 1111 1117
⚠️ These are test numbers only. This validator checks format, not if a card is active or has funds.
How Credit Card Validation Works
Our credit card validator uses the Luhn algorithm (also called mod-10 algorithm) to verify that a credit card number is mathematically valid. This is the same method used by banks and payment processors worldwide.
Luhn Algorithm Steps:
- Starting from the rightmost digit, double every second digit
- If doubling results in a number greater than 9, subtract 9
- Sum all the digits together
- If the total is divisible by 10, the card number is valid
What This Validator Checks:
- ✓ Card number length (13-19 digits)
- ✓ Luhn algorithm checksum
- ✓ Card type detection (Visa, Mastercard, Amex, etc.)
- ✗ Does NOT check if card is active or has funds
- ✗ Does NOT verify expiration date or CVV
Frequently Asked Questions
Is this credit card validator safe to use?
Yes. All validation happens in your browser using JavaScript. Your card number is never sent to our servers or stored anywhere. However, never enter real credit card numbers on any website you don't trust.
Does validation mean the card will work for payments?
No. This validator only checks if the card number format is mathematically correct using the Luhn algorithm. It does NOT verify if the card is active, has sufficient funds, or is authorized for transactions. Only the card issuer can confirm that.
Which card types can this validator detect?
Our validator can identify Visa, Mastercard, American Express, Discover, Diners Club, and JCB cards based on their unique number patterns. However, validation works for any card that uses the Luhn algorithm.
Why do some valid-looking numbers fail validation?
Credit card numbers contain a check digit calculated using the Luhn algorithm. If someone types a random 16-digit number, there's only a 10% chance it will pass Luhn validation. Real cards are generated to pass this check.