The design of the credit card itself has become a major selling point in recent years. The value of the card to the issuer is often related to the customer’s usage of the card, or to the customer’s financial worth. This has led to the rise of Co-Brand and Affinity cards, where the card design is related to the “affinity” (a university or professional society, for example) leading to higher card usage. In most cases a percentage of the value of the card is returned to the affinity group.
A growing field of numismatics (study of money), or more specifically exonumia (study of money-like objects), credit card collectors seek to collect various embodiments of credit from the now familiar plastic cards to older paper merchant cards, and even metal tokens that were accepted as merchant credit cards. Early credit cards were made of celluloid plastic, then metal and fiber, then paper, and are now mostly polyvinyl chloride (PVC) plastic. However the chip part of credit cards is not made from plastic but from metals.
The size of most credit cards is 85.60 mm × 53.98 mm (3.370 in × 2.125 in) and rounded corners with a radius of 2.88–3.48 mm, conforming to the ISO/IEC 7810 ID-1 standard, the same size as ATM cards and other payment cards, such as debit cards.
Credit cards have a printed or embossed bank card number complying with the ISO/IEC 7812 numbering standard. The card number’s prefix, called the Bank Identification Number, is the sequence of digits at the beginning of the number that determine the bank to which a credit card number belongs. This is the first six digits for MasterCard and Visa cards. The next nine digits are the individual account number, and the final digit is a validity check code.