What Is a MAC Address?

What a MAC address actually is

When two devices talk on the same local network — your laptop and your router, for example — they do not address each other by IP address at the lowest level. They address each other by MAC address. The MAC address operates at Layer 2, the data link layer of the OSI model, and identifies a specific physical (or virtual) network interface. Because of this, a MAC address is sometimes called a physical address, a hardware address, or an Ethernet address.

The manufacturer of a network chip assigns each adapter a value known as the burned-in address (BIA), stored in the device firmware. In principle, no two adapters anywhere in the world should share the same burned-in MAC address. That global uniqueness is what lets a switch reliably forward a frame to exactly one port instead of flooding it everywhere.

A single computer often has several MAC addresses, not just one. A typical laptop has a separate MAC for its Wi-Fi adapter, its wired Ethernet adapter and its Bluetooth radio. Virtual machines, containers and software network bridges each get their own MAC address too, so it is normal to see many entries when you list a system's interfaces.

The 48-bit format and the OUI vendor prefix

A standard MAC address (technically an EUI-48 identifier) is 48 bits long. Forty-eight bits is six bytes, and each byte is written as two hexadecimal digits, giving the familiar twelve-character form. The same address can appear in several notations depending on the vendor or operating system:

• Colon-separated: 00:1A:2B:3C:4D:5E (common on Linux, macOS and most documentation)
• Hyphen-separated: 00-1A-2B-3C-4D-5E (common on Windows)
• Dot-separated: 001A.2B3C.4D5E (common on Cisco equipment)

All three describe the identical 48-bit value; only the punctuation differs. With 48 bits there are 2^48 possible combinations — over 281 trillion — which is why the supply of unique hardware addresses has lasted so long.

How the 48 bits are split

The address divides cleanly into two 24-bit halves, each serving a different purpose:

The first half is the OUI, short for Organizationally Unique Identifier. The IEEE Registration Authority sells OUI blocks to hardware makers, so the leading three octets of any MAC address reveal which company built the chip. For instance, many Apple devices use OUIs that begin with prefixes the IEEE registered to Apple, and Cisco, Intel and Samsung each have their own registered ranges. The manufacturer then assigns the trailing 24 bits to individual units coming off the line. You can paste a MAC address into our MAC Address Lookup tool to resolve the OUI to its registered vendor.

Two control bits worth knowing

The very first byte of a MAC address carries two special flag bits that explain a lot of real-world behavior:

• The I/G bit (least-significant bit of the first octet) marks whether the address is unicast (one device) or multicast (a group of devices). The all-ones broadcast address FF:FF:FF:FF:FF:FF reaches every device on the segment.
• The U/L bit (second-least-significant bit of the first octet) marks whether the address is universally administered (a real, IEEE-assigned burned-in address) or locally administered (set by software). Randomized and spoofed MAC addresses set this bit, which is one technical signal that an address was not assigned by a manufacturer.

If you ever need to generate test addresses with the correct bits set, the MAC Address Generator produces valid, well-formed values you can use in lab and configuration work.

MAC address vs IP address

MAC addresses and IP addresses are often confused because both identify devices, but they work at different layers and solve different problems. The simplest way to remember it: the IP address gets your data to the right network, and the MAC address gets the frame to the right device on that network. They work together on every single connection you make.

How do the two cooperate? When your computer wants to send data to another device on the same network, it knows the destination IP address but needs the matching MAC address to actually deliver the frame. On IPv4 it uses the Address Resolution Protocol (ARP) to ask "who has this IP?" and learn the corresponding MAC. IPv6 does the same job with Neighbor Discovery Protocol (NDP). For traffic leaving the local network, your device sends the frame to the router's MAC address; the router then strips the Layer 2 framing and forwards the packet onward by IP. This is also why remote servers never learn your device MAC — it is replaced at the first hop. To see what the wider internet sees instead, run our IP Lookup tool.

How to find your MAC address

Finding your MAC address is quick on every major platform. Note that if your device uses MAC randomization (covered below), the address shown in your Wi-Fi network details may be a private, per-network value rather than the burned-in hardware address.

Windows

There are two reliable methods on Windows 10 and 11:

1. Press Windows + R, type cmd, and press Enter.
2. In the Command Prompt, type ipconfig /all and press Enter.
3. Find your adapter (for example "Wireless LAN adapter Wi-Fi") and read the value next to Physical Address, shown in hyphen notation like 00-1A-2B-3C-4D-5E.

Alternatively, open Settings → Network & internet, click your active connection, and scroll to the hardware properties, where the MAC address is listed alongside the IP details. The command getmac /v also prints a clean list of every adapter and its MAC.

macOS

1. Open System Settings (or System Preferences on older versions).
2. Go to Network and select your active interface, such as Wi-Fi.
3. Click Details (or Advanced) and open the Hardware tab; the MAC address is shown there.

From the Terminal you can also run ifconfig en0 | grep ether (Wi-Fi is usually en0 on laptops). The value after ether is your MAC address.

iPhone and iPad (iOS / iPadOS)

1. Open Settings → General → About and look for Wi-Fi Address. This is the device's underlying hardware MAC.
2. To see the address actually used on a given network, open Settings → Wi-Fi, tap the (i) next to the network, and read the Wi-Fi Address there. With "Private Wi-Fi Address" enabled, this will be a randomized value specific to that network.

Android

1. Open Settings → About phone (or About device) and look under Status for the Wi-Fi MAC address.
2. For the per-network value, open Settings → Network & internet → Wi-Fi, tap the connected network, and view its details. Android labels its randomized option "Use randomized MAC" or "Use device MAC".

Menu names vary slightly by manufacturer (Samsung One UI, Google Pixel and others differ), but the MAC address always lives in the Wi-Fi or About section.

Linux

Open a terminal and run ip link. Each interface lists a link/ether line followed by its MAC address. The older ifconfig command shows the same value after the ether (or HWaddr) label.

On your router

Your router's admin page keeps a table of every device currently on the network, pairing each assigned IP address with the device's MAC address and often a hostname. This is the place to confirm which physical device holds which address, and it is invaluable when you are setting up DHCP reservations or troubleshooting an unfamiliar device on your Wi-Fi.

MAC randomization and privacy

For most of networking history, every device broadcast its real, permanent MAC address whenever it scanned for or connected to Wi-Fi. That created a privacy problem: because the address never changed, any Wi-Fi operator — a store, an airport, a shopping mall — could recognize and follow the same device across days, locations and visits, building a movement profile without consent.

To close that gap, the major platforms adopted MAC randomization. Instead of advertising the burned-in hardware address, the device generates a different, software-defined MAC (one with the locally administered U/L bit set):

• iOS and iPadOS use a feature called Private Wi-Fi Address, on by default, which assigns a stable but unique MAC per network. The address stays consistent for that network so things like captive portals and parental controls keep working, but a different network sees a different address.
• Android randomizes the MAC per network by default and can be set to rotate the address periodically for even stronger separation between sessions.
• Windows offers Random hardware addresses, which can be enabled globally or per network, including a daily-rotating option for networks you connect to often.
• Linux supports randomization through NetworkManager and similar tools, both during scanning and when associated with a network.

Randomization is a meaningful privacy win, but it has practical side effects. Networks that rely on a fixed MAC — for MAC-address allow-lists, device-based parental controls, or DHCP reservations — may not recognize a randomized device. In those cases you can usually turn off the private address for that specific network, which makes the device fall back to its real hardware MAC. It is also worth remembering what randomization does not do: it hides you from local Wi-Fi tracking, but it has no effect on how websites identify you over the internet. That is governed by your IP address and browser fingerprint, not your MAC.

Related tools & reading

• MAC Address Lookup — resolve a MAC address OUI to its registered hardware vendor.
• MAC Address Generator — create valid, correctly formatted MAC addresses for testing and configuration.
• IP Lookup — see the public IP and approximate location the internet associates with an address.
• DNS Lookup — query A, AAAA, MX, TXT and other records for any domain.
• DNS Health Check — audit a domain's DNS configuration for common problems.
• DNS Propagation Checker — see whether a DNS change has reached resolvers worldwide.
• What Is an IP Address? — the companion guide to the Layer 3 side of addressing.
• Back to the Learning Center