Credit Card Number Check

Credit Card Numbers Check - When making a purchase online using your credit card, the merchant will often perform what is known as a credit card numbers check. This check is often performed automatically by a script or program. A credit card number check basically works by taking each individual block of numbers on your card, and checking them against data in the computer. These numbers are encoded with information such as what kind of card you are using (MasterCard, Visa, American Express, etc), what bank the card comes from, and how much the credit limit is on the card.

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Whenever you make a purchase and your card is authorized, the merchant is performing a credit card numbers check, as well as performing an authorization check. The first part of the check simply tells the merchant whether this is a valid card or not. If this number doesn’t match up, then it will not accept the card. The second part of the check sends a packet of information to the actual credit card company, which is a packet that basically says "can this user spend this amount of money on this card?” The credit card company will then either reply in the affirmative or will decline the credit card customer due to insufficient funds or other possible problems

Most credit card numbers check systems use what is known as a "Check digit". This is a digit added to a number (either at the beginning or the end) to validate the authenticity of the number in question. An algorithm is applied to the numbers which should yield the same number as the check digit. If this credit card numbers check shows a different number as the check digit, then the card will not be accepted by the merchants.

By understanding how a credit card numbers check works, you can actually verify your own number. This can be useful knowledge if you ever have your card turned down for being invalid. You can do a credit card numbers check yourself to verify this information or to find out if you possibly gave the wrong numbers. You can find out more information on the algorithm used in a credit card numbers check by going to http://www.beachnet.com/~hstiles/cardtype.html and checking out their algorithm chart. This chart will explain the algorithm used to do a credit card numbers check and show you how you can perform the same check yourself.