What Is a MAC Address? Format and How It Works
A MAC (Media Access Control) address is a unique 48-bit identifier assigned to a device's network interface by the manufacturer. Written as six pairs of hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E), it identifies hardware on a local network — unlike an IP address, which can change as the device moves between networks.
MAC addresses are how devices find each other on a local network. Here's how they work.
The 48-Bit Format
A MAC address is 48 bits, shown as 12 hex digits in six groups:
00:1A:2B:3C:4D:5E
└──────┘ └──────┘
OUI Device ID
- First 24 bits (OUI) — the Organizationally Unique Identifier, assigned to the manufacturer (Apple, Intel, Cisco, etc.) by the IEEE. You can often identify a device's maker from this prefix.
- Last 24 bits — a unique serial assigned by that manufacturer to the specific interface.
Separators vary by vendor: 00:1A:2B:3C:4D:5E, 00-1A-2B-3C-4D-5E, or 001A.2B3C.4D5E. Generate sample addresses with our Random MAC Generator.
MAC Address vs IP Address
The two are often confused but operate at different layers:
| MAC address | IP address | |
|---|---|---|
| Layer | Data link (Layer 2) | Network (Layer 3) |
| Scope | Local network segment | Across networks/internet |
| Assigned by | Manufacturer (burned in) | Network / DHCP |
| Changes? | Generally fixed | Changes by network |
| Analogy | Like a serial number | Like a mailing address |
A useful analogy: the MAC address is who the device is (fixed identity), while the IP address is where it currently is (its location on the network). Learn more in What Is an IP Address?.
How MAC Addresses Are Used
- Local delivery — switches use MAC addresses to forward frames to the right device on a LAN.
- ARP — the Address Resolution Protocol maps an IP address to a MAC address so data can reach the device.
- DHCP — servers can assign a consistent IP to a specific MAC.
- MAC filtering — routers can allow/deny devices by MAC (a weak security measure on its own).
Can a MAC Address Be Changed?
Yes. Although the hardware MAC is "burned in," operating systems let you spoof it in software, and modern phones use randomized MAC addresses per Wi-Fi network to protect privacy (so you can't be tracked across locations). This is why the MAC your phone shows for a network may not match the hardware address.
How to Find Your MAC Address
Quickly:
- Windows:
ipconfig /all→ "Physical Address." - macOS: System Settings → Wi-Fi → Details.
- iPhone: Settings → General → About → Wi-Fi Address.
For the full per-device walkthrough, see How to Find Your MAC Address.
Frequently Asked Questions
What is a MAC address? A unique 48-bit identifier assigned to a device's network interface by the manufacturer, used to identify hardware on a local network.
What does a MAC address look like?
Six pairs of hexadecimal digits separated by colons or hyphens, e.g. 00:1A:2B:3C:4D:5E.
What is the difference between a MAC address and an IP address? A MAC address is a fixed hardware ID used on the local network (Layer 2); an IP address is assigned by the network and used to route across networks (Layer 3).
Can a MAC address be changed? The hardware address is fixed, but it can be spoofed in software, and modern devices randomize their MAC per network for privacy.
What is a MAC address used for? Delivering data to the right device on a local network, ARP resolution, DHCP reservations, and MAC-based access filtering.
Related Reading
A MAC address is the fixed, factory-set name of a network interface. Pair that with a changeable IP address, and you have the two identifiers every networked device needs to communicate.