MAC Address Generator

About this tool

Generate random MAC addresses for testing and lab work, or look up which vendor the first three bytes of a MAC belong to. Everything runs in your browser.

What a MAC address is. A Media Access Control address is a 48-bit identifier assigned to a network interface — the hardware-level address a switch or Wi-Fi access point uses to move a frame to the right port. It's written as six pairs of hex digits. The first three bytes are the OUI (Organizationally Unique Identifier), assigned to a manufacturer by the IEEE; the last three are chosen by that manufacturer per device.

Two bits in the first byte carry meaning:

• Locally administered bit. When set, the address was assigned by software or an administrator rather than burned in at the factory. This is the correct choice for a fake or test MAC — it guarantees the address can't clash with any real vendor-assigned one. Leave it on unless you specifically need to mimic a real device's OUI.
• Multicast bit. When set, a frame to this address is meant for a group of devices, not one. A real network card's own address is always unicast (this bit clear). Only set it if you're testing multicast handling.

Format variants. The same address is written several ways: colon-separated (AA:BB:CC:DD:EE:FF, Unix/Linux), hyphen-separated (AA-BB-CC-DD-EE-FF, Windows), Cisco dotted (AABB.CCDD.EEFF), or bare hex. They're interchangeable — pick whatever the system you're testing expects.

MAC randomisation. Modern phones and laptops rotate a random, locally-administered MAC per Wi-Fi network for privacy, so a device no longer broadcasts one stable hardware address everywhere it goes. The addresses this tool generates with "locally administered" on are the same kind.

The vendor lookup checks a curated shortlist — Apple, Samsung, Intel, Cisco, Raspberry Pi, common hypervisors, and other frequently-seen OUIs — not the full IEEE registry of 40,000+ entries. A MAC that isn't recognised isn't necessarily invalid; it just isn't on the shortlist.

For IP-level planning, use the subnet calculator; to see your own connection details, What Is My IP. For other random test identifiers, the UUID generator.

Frequently asked questions

What does "locally administered" mean?

A bit in the first byte marks the address as software-assigned rather than factory-assigned. Generating a locally administered address is the standard way to make a test MAC that can't collide with a real vendor's range.

What does "multicast" mean?

Another bit marks a frame as destined for a group of devices rather than one. Real interface addresses are always unicast — leave this off unless you're testing multicast.

Why doesn't the vendor lookup recognise my MAC?

It only checks a curated shortlist of common vendors, not the full 40,000-entry IEEE OUI registry. An unrecognised OUI isn't necessarily invalid.

Which address format should I use?

Colon-separated on Linux/macOS, hyphen-separated on Windows, dotted on Cisco gear. They represent the same address — match the target system.

Can I use a generated MAC on a real device?

You can set a locally-administered MAC on most operating systems (MAC spoofing), which is legitimate for privacy or lab testing. Don't use it to impersonate another specific device on a network you don't control.

Are the addresses saved or sent anywhere?

No. Both generation and lookup run entirely in your browser.