MAC Address Lookup
Identify the device vendor from a MAC address prefix (OUI).
MAC Address Lookup identifies the manufacturer of a network device from the first part of its MAC address. It is handy for figuring out what a device on your LAN actually is — a router, laptop, phone or IoT gadget — or for checking which vendor an unknown device that just joined your network comes from.
The first 6 hex digits of a MAC address are called the OUI (Organizationally Unique Identifier), assigned to manufacturers by the IEEE. This tool extracts just the OUI from your input, queries a public vendor database, and shows the matching manufacturer name. Any separator works — colons (:), hyphens (-) or dots (.). To check whether a device's IP falls in a private range, pair this with the Private IP Checker.
The free external API is limited to about one request per second. Results are cached per OUI for 24 hours.
MAC address and OUI structure
A MAC address is 48 bits (12 hex digits) and is unique per network interface. It typically splits into two parts:
- First 24 bits (6 digits) — OUI: the identifier the IEEE assigns to a vendor. This is the part that reveals the manufacturer.
- Last 24 bits (6 digits) — NIC: a serial value the vendor assigns to each device. It is not used for vendor lookup.
For example, in 00:1A:2B:3C:4D:5E the OUI is 00:1A:2B, and that value identifies the vendor. The forms 00:1A:2B:3C:4D:5E, 00-1A-2B-3C-4D-5E and001A.2B3C.4D5E all refer to the same address.
Things to know about lookups
- External API rate limit: vendor data comes from a free public API limited to roughly one request per second. Pause briefly between repeated lookups.
- Local/random MAC: when a specific bit (locally administered) in the second hex digit is set, the MAC is not a real vendor OUI. Modern phones use such randomized MACs for Wi-Fi privacy.
- Not registered: if the OUI is not in the database, it shows as unregistered. It may be a new allocation or a private range.
Reading the second hex digit to classify a MAC
The two lowest bits of the OUI's first byte decide what kind of MAC you have. The least significant bit (I/G) marks unicast vs. multicast; the next bit (U/L) marks global (IEEE-assigned) vs. locally administered. So glancing at the second hex digit alone tells you whether a vendor lookup is even meaningful.
| 2nd digit | Low 2 bits | Meaning | Vendor lookup |
|---|---|---|---|
0,4,8,C | 00 | Unicast, global (IEEE-assigned) | Yes — real OUI |
2,6,A,E | 10 | Unicast, locally administered (random) | No — no vendor |
1,5,9,D | 01 | Multicast, global | Special — e.g. 01:00:5E (IPv4 multicast) |
3,7,B,F | 11 | Multicast, locally administered | No |
Note the broadcast address FF:FF:FF:FF:FF:FF also has F (multicast) as its second digit, so it has no vendor either.
A lookup walked through
Suppose you enter 3C-22-FB-12-34-56. The tool processes it in this order:
- 1. Strip the separators (
-) and normalize to 12 digits →3C22FB123456. - 2. Second digit
C→ low 2 bits00, so it is a global unicast address worth looking up. - 3. Extract the first 6 digits, OUI
3C:22:FB→ query the vendor DB. - 4. Result: Apple, Inc. (this OUI is one of Apple's assigned blocks).
By contrast, 3A-22-FB-12-34-56 has A as its second digit, so it is judged a locally administered (random) MAC and returns no vendor even though the rest looks identical.
Common pitfall
- Don't panic when a Wi-Fi MAC seen on an iPhone or Android returns no vendor. Modern OSes generate a randomized (locally administered) MAC per SSID, whose second digit is almost always
2/6/A/E. To see the real hardware MAC you must turn off the "Private Wi-Fi Address" option in settings. - A matched OUI does not prove that company "built" the device. You often see the chipset (Wi-Fi module) maker rather than the finished-product brand, so the two can differ.