NetKit

MAC address lookup

Find the vendor of any MAC address or OUI from the IEEE registry (54,000+ prefixes). Look up one address or a whole list, search prefixes by manufacturer, or generate random MACs.

OUI vendor lookup
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Paste a MAC address in any common format.

Anatomy of a MAC address

A MAC (Media Access Control) address is 48 bits, written as six bytes. The first three are the OUI, the last three are assigned by the manufacturer. Two bits in the very first byte carry meaning:

  • Bit 0 (I/G): 1 = multicast/group address (e.g. 01:00:5E:… for IPv4 multicast, FF:FF:FF:FF:FF:FF for broadcast).
  • Bit 1 (U/L): 1 = locally administered. Virtual machines, containers and privacy-MAC Wi-Fi clients use these.

MA-L, MA-M and MA-S blocks

The IEEE sells three block sizes. An MA-L (the classic OUI) fixes 24 bits and leaves about 16.7 million addresses; MA-M fixes 28 bits (about 1 million); MA-S fixes 36 bits (4,096), sized for small manufacturers. This lookup matches MA-L prefixes, which cover the great majority of devices.

Find your own: ip link (Linux), ifconfig en0 ether (macOS), getmac /v (Windows). Find neighbours on your LAN with arp -a.

Vendor data: IEEE Registration Authority MA-L listing, bundled at build time.

Questions people ask

How does a MAC address lookup work?
The first 24 bits (six hex digits) of a MAC address are the Organizationally Unique Identifier (OUI), bought from the IEEE Registration Authority by the manufacturer. Looking up the OUI names the company that made the network interface.
Why does my phone's MAC show "locally administered" and no vendor?
iOS, Android, Windows and macOS use randomised "private" MAC addresses on Wi-Fi to prevent tracking. They set the locally-administered bit (second-lowest bit of the first byte), so the second hex digit is 2, 6, A or E, and they have no vendor.
What formats can I paste?
Any: 00:1A:2B:3C:4D:5E, 00-1A-2B-3C-4D-5E, 001A.2B3C.4D5E (Cisco) or plain hex. Only the first six digits are needed.
Can I find a device's location from its MAC?
No. MAC addresses never leave your local network segment; routers replace them hop by hop. They identify hardware, not location.