What is the standard size of a MAC address in a computer network?

Concept

A Media Access Control (MAC) address identifies a network interface at the data-link layer. The commonly used IEEE 802 address format is EUI-48, organized as six octets.

One octet contains 8 bits, and each octet is written as two hexadecimal digits. Therefore, a six-octet address is written as 12 hexadecimal digits.

Application

1. Count the octets in the EUI-48 format: 6 octets.

2. Convert octets to bits: 6 × 8 = 48 bits.

3. Convert the same format to hexadecimal digits: 6 × 2 = 12 hexadecimal digits.

Cross-check and contrast

• 32 bits make four octets and are the length of an IPv4 address, not an EUI-48 identifier.

• 16 bits make two octets, which is shorter than the six-octet EUI-48 format.

• 48 bits make six octets and 12 hexadecimal digits, matching both descriptions of EUI-48.

• “More than one of the above” does not apply because only one listed numeric length equals six octets.

• “None of the above” does not apply because 48 bits is present among the listed values.

Result: the standard MAC address size asked for here is 48 bits.