What Is a MAC Address? A Complete Beginner's Guide

A MAC address (Media Access Control address) is a unique 48-bit identifier assigned to a network interface — your Wi-Fi card, Ethernet port or Bluetooth radio. It is the hardware name tag that lets devices talk to each other on a local network.

How a MAC address looks

A MAC address is usually written as six pairs of hexadecimal digits, for example 00:1A:2B:3C:4D:5E. You may also see dashes (00-1A-2B-3C-4D-5E) or dots (001A.2B3C.4D5E) — they all mean the same thing.

The two halves of a MAC address

The first three bytes (00:1A:2B) are the OUI — the Organizationally Unique Identifier — which the IEEE assigns to a specific manufacturer. The last three bytes are chosen by that manufacturer to make each device unique. Because the OUI maps to a vendor, you can look up any MAC address to discover who made the device.

MAC address vs IP address

A MAC address is permanent and tied to the hardware; an IP address is assigned by the network and can change. MAC operates at Layer 2 (the data-link layer) for local delivery, while IP operates at Layer 3 for routing across networks.

Look up any MAC address

Paste a MAC address into our free MAC lookup tool to instantly see the manufacturer, the OUI prefix, the IEEE block type and more.