MAC address lookup, find the maker.

A MAC address lookup finds the company behind a MAC address by matching its first digits, called the OUI or prefix, against the public registry kept by the IEEE. A MAC address is the 48-bit hardware address of a network adapter, written as 12 hex digits such as 00:1A:2B:3C:4D:5E. The registry names the company that was given that block of addresses, which is usually the maker of the network chip or device. This page does the lookup in your browser, for one address or for a long list, and also tells you when an address is random or a group address, which a plain name lookup cannot.

How to use it

1. Paste an address into the box. A list works too, with one address per line, or several in a block of text such as a log. Try One address or A list to see examples.
2. Read the result. A single address gets a card with the maker, the registry block, the prefix and the two bits. A list gets a table.
3. Choose Show addresses as to get colons, dashes, dots or no separator, in lower case or capitals. Click any address or spelling to copy it.
4. For a list, press Download CSV or Copy as a table. Tick Show each address once to remove repeats.
5. To go the other way, type part of a company name under Find the prefixes of a company and read the list of prefixes registered to it.

What formats it reads

Pairs separated by colons (00:1A:2B:3C:4D:5E), dashes (00-1A-2B-3C-4D-5E), spaces, three groups of four with dots (001a.2b3c.4d5e, the style some Cisco tools print), or 12 digits in a row. It also reads 16-digit EUI-64 addresses. If you paste only a prefix, such as 00:1A:2B or a 7 or 9 digit prefix, it looks that up directly. Any line that holds no address is listed as not a MAC address.

MA-L, MA-M and MA-S

The IEEE sells blocks in three sizes. According to the IEEE tutorial on EUI, OUI and CID (checked 18 Oct 2026), an MA-L block holds 2 to the 24th addresses, an MA-M block 2 to the 20th and an MA-S block 2 to the 12th. An MA-L has a 24-bit prefix, an MA-M a 28-bit one and an MA-S a 36-bit one. The small blocks sit inside a 24-bit prefix that the IEEE keeps for itself, so the lookup tries the 36-bit prefix first, then the 28-bit, then the 24-bit. For 00:1B:C5:00:0A:BC the 24-bit prefix 00:1B:C5 is listed to the IEEE Registration Authority, and the 36-bit prefix 00:1B:C5:00:0 is listed to a smaller company. That is why pasting a full address gives a better answer than pasting only three bytes.

Reading the two bits

The first byte of a MAC address carries two flags (IEEE tutorial, same source). The lowest bit is the I/G bit: 0 means a single device, 1 means a group address. The next bit is the U/L bit: 0 means universal, assigned through the registry, and 1 means local, set by software or a network administrator. A quick rule is to look at the second hex digit of the address. 0, 4, 8 and C mean a universal single device. 1, 5, 9 and D mean a universal group address. 2, 6, A and E mean a local single device, and 3, 7, B and F mean a local group address.

The IEEE says a maker may build group addresses from its own prefix by setting the group bit. For that reason a group address is looked up with the group bit cleared, and 01:00:5E is read through 00:00:5E, which the registry lists to ICANN, IANA Department.

Why many phones show a random address

Modern phones do not use their real hardware address on Wi-Fi. Apple's support page (checked 18 Oct 2026) says an iPhone identifies itself to each network using a different Wi-Fi address, and can keep it fixed or rotate it. Android's documentation (checked 18 Oct 2026) says Android 10 and later use a randomised MAC address by default, with the local bit set to 1 and the group bit to 0. Such an address will show as locally administered with no maker, and it cannot be traced to a phone brand. The same phone shows its real address only if you turn the private address off for that network.

What the result does not tell you

• It does not identify a person or a device owner. It names who was given the block of addresses. Names such as a chip maker or a module supplier are common, so the brand on the box can differ.
• Private entries. Some blocks are listed as Private. No company name is public for those.
• A snapshot. The file was read from the IEEE listings on 18 Oct 2026. Blocks assigned later are not in it.
• Company IDs. The IEEE also lists company IDs (CIDs), which are used to build local addresses. They are not in this file.

To turn a hex value into other bases, try the number base converter, and the binary translator shows bytes as bits.