The Traditional Payment Card Dimensions
The dimensions of a traditional credit card (3-3/8 x 2-1/8 inches or 85 x 54 mm) conform to the golden ratio, also known as the Greek letter Rho: L / W = 1.6 (rounded).
This is the ratio found in the Fibonacci sequence, leveraged by Leonardo Da Vinci, and historically thought to represent the perfect balance or harmony in nature and beauty.
The 16 Digit Payment Card Number
Most general-purpose payment cards today use a 16-digit card number. Historically, some were 13 and today can be as long as 19.
With some exceptions, the first digit of the 16-digit card number indicates the payment network through which transactions from a card flow:
2 – Russian, other former Soviet-bloc payment networks, and others
3 – American Express, JBC, and a few others
4 – Visa
5 – MasterCard (also "2" as of 11/3/ 2014)
6 – Discover
The first 8 digits for Visa and MasterCard, are called the BIN number (Business ID Number), as of April 2022. Prior to 2022, the BIN length was for many years 6 digits, and only 4 digits before that. Each BIN (unique 8 digit combination) is registered to a specific issuer and indicates to which issuer an authorization and transaction need to be routed by the payment network (analogous to a routing number for paper checks).
The second set of 8 digits is assigned by the individual issuer and combined with the BIN number, comprise the cardholder account number.
The last digit of the 16-digit card number is part of the total cardholder account number but is a check digit that is assigned by an algorithm (not at the discretion of the issuer). The check digit provides a first-line protection that a 16-digit card number does not have any data entry errors and is not an intentionally fabricated account number.
© 2023 Robert Holden
The dimensions of a traditional credit card (3-3/8 x 2-1/8 inches or 85 x 54 mm) conform to the golden ratio, also known as the Greek letter Rho: L / W = 1.6 (rounded).
This is the ratio found in the Fibonacci sequence, leveraged by Leonardo Da Vinci, and historically thought to represent the perfect balance or harmony in nature and beauty.
The 16 Digit Payment Card Number
Most general-purpose payment cards today use a 16-digit card number. Historically, some were 13 and today can be as long as 19.
With some exceptions, the first digit of the 16-digit card number indicates the payment network through which transactions from a card flow:
2 – Russian, other former Soviet-bloc payment networks, and others
3 – American Express, JBC, and a few others
4 – Visa
5 – MasterCard (also "2" as of 11/3/ 2014)
6 – Discover
The first 8 digits for Visa and MasterCard, are called the BIN number (Business ID Number), as of April 2022. Prior to 2022, the BIN length was for many years 6 digits, and only 4 digits before that. Each BIN (unique 8 digit combination) is registered to a specific issuer and indicates to which issuer an authorization and transaction need to be routed by the payment network (analogous to a routing number for paper checks).
The second set of 8 digits is assigned by the individual issuer and combined with the BIN number, comprise the cardholder account number.
The last digit of the 16-digit card number is part of the total cardholder account number but is a check digit that is assigned by an algorithm (not at the discretion of the issuer). The check digit provides a first-line protection that a 16-digit card number does not have any data entry errors and is not an intentionally fabricated account number.
© 2023 Robert Holden