MAC Address Vendor Lookup

It finds the organization that the IEEE Registration Authority assigned a MAC address prefix to, and explains the address itself. Each result shows the normalized address, the vendor, the assignment block (MA-L /24, MA-M /28 or MA-S /36), the matched prefix, whether the address is unicast, multicast or broadcast, and whether it is universally or locally administered.

1. 1.Paste a MAC address in colon (00:1A:2B:3C:4D:5E), hyphen (00-1A-2B-3C-4D-5E), Cisco dotted (001A.2B3C.4D5E) or plain hex (001A2B3C4D5E) form; letter case does not matter.
2. 2.Read the vendor, assignment block and address bits in Results, and copy any value with its copy button.
3. 3.Paste one address per line, for example from an ARP table, DHCP leases or an inventory export, to look up to 1,000 addresses at once.
4. 4.Copy or download the list results as CSV.

IEEE assigns large MA-L blocks (24-bit prefix, often called an OUI), medium MA-M blocks (28-bit) and small MA-S blocks (36-bit). Smaller blocks are carved out of larger ones, so the lookup checks MA-S first, then MA-M, then MA-L, and reports the most specific match. A prefix that appears in none of them is reported as not found instead of guessed.

When the U/L bit (second-lowest bit of the first octet) is set, the address was set by software rather than burned in by a manufacturer. Phones with Wi-Fi privacy, virtual machines and containers use these, so a vendor name would be meaningless. When the I/G bit (lowest bit) is set, the address names a multicast group; the vendor shown is the organization that owns the prefix. FF:FF:FF:FF:FF:FF is the broadcast address.

Vendor names come from a dated snapshot of the public IEEE MA-L, MA-M and MA-S registries, published on this site. The page downloads the snapshot once when you look up the first address; every address is then matched in your browser and never sent anywhere. The snapshot date is shown under the results. Assignments change over time, and a vendor match does not prove which device uses an address.