A MAC address, short for Media Access Control address, is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. It is a 12-digit hexadecimal number assigned to each device connected to the network. MAC addresses are used in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth. They are primarily assigned by device manufacturers and are often referred to as the burned-in address, Ethernet hardware address, hardware address, or physical address.

Each network interface in a device is assigned a unique MAC address, so its possible for a device to have more than one MAC address. For example, if a laptop has both an Ethernet cable port and built-in Wi-Fi, there will be two MAC addresses shown in the system configuration. MAC addresses are required when trying to locate a device or when performing diagnostics on a network device.

MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator. They are stored in hardware, such as the cards read-only memory, or by a firmware mechanism. Many network interfaces support changing their MAC address. The address typically includes a manufacturers organizationally unique identifier (OUI).

To find the MAC address of a device, you can check the system settings, general information, or network settings/status of the device. Occasionally, the MAC address is printed on a label affixed to the bottom of a device. There are three types of MAC addresses: unicast, multicast, and broadcast.

MAC addresses are different from IP addresses, which are used to identify a device on a network for different purposes. While MAC addresses are like Vehicle Identification Numbers (VINs), which are unique to each vehicle, IP addresses are like postal addresses, which can change depending on the location of the device.