This demonstration shows how a credit card number can be validated to be sure it is a number associated with a true card number. It will not tell if the credit card is valid - it only checks to see that the number does not violate any Luhn check sum. This is useful when helping a customer enter his card number. If the customer makes a mistake it will tell him. Using our simple credit card number validation by Luhn check sum.

All aspects of the card can be checked but for this demonstration only the number will be validated. Valid Numbers for this demonstration are:

VISA 4444 5555 6666 7753

Discover 6011 2222 3333 4444

Master Card 5555 6666 7777 8884

American Express 3711 2222 3333 439

The numbers above are valid Luhn numbers but you can try you luck at creating your own valid Luhn Check Sum Number.

Remember all VISA cards start with a 4, MasterCards start with a 5, Discover Starts with a 6 and American Express starts with a 3. Also the Card Verification numbers for VISA, Master Card and Discover are 3 digits while American Express is a 4 digit number.