What is an OUI?
The first 3 bytes (24 bits) of a MAC address, registered to a manufacturer by the IEEE — the remaining 3 bytes are assigned by that manufacturer.
MAC Address Lookup
Input
B8:27:EB:12:34:56unicast
Lookup
Formats
- Colon
- B8:27:EB:12:34:56
- Hyphen
- B8-27-EB-12-34-56
- Cisco dot
- b827.eb12.3456
- Bare
- B827EB123456
Address
- OUIvendor prefix
- B8:27:EB
- NICdevice ID
- 12:34:56
- Vendor
- Raspberry Pi Foundation
- Type
- Unicast
- Administration
- Universally administered (burned-in)
About this MAC Address Lookup
Look up the manufacturer behind a MAC address's OUI prefix, and inspect its unicast/multicast and universal/local administration bits.
Vendor lookups run against the full IEEE registry — all 58,000+ MA-L, MA-M, MA-S and IAB assignments — loaded into this page, so no address is sent anywhere. Sub-allocated blocks are matched at their real granularity (36-bit and 28-bit assignments before the 24-bit parent), which is what lets a small manufacturer resolve to its own name instead of to the registration authority that holds the parent block. Switch to Vendor search to list every block a manufacturer holds, or to Batch to look up a whole list of addresses at once and export the results as CSV.
FAQ
How large/current is this tool's vendor database?
The complete IEEE registry — all 58,325 assignments across MA-L (24-bit), MA-M (28-bit), MA-S (36-bit) and the legacy IAB blocks, bundled into the page as a dated snapshot. An unrecognized prefix therefore does mean an unregistered one, and the tool distinguishes three kinds of miss rather than collapsing them into 'unknown': absent from the registry, registered but with the holder's name withheld, or a sub-allocated range with no registrant of its own.
Can I find the MAC address range a specific vendor like Apple or Cisco owns?
Yes — switch to Vendor search and type the manufacturer's name, and every block that vendor holds is listed. Each 24-bit OUI covers about 16.7 million device addresses; 28- and 36-bit sub-allocations cover proportionally smaller ranges. Large vendors hold hundreds of blocks, so the list is capped at 250 results, and when it is capped the true match count is shown beside it. Selecting a result jumps back to single lookup with that prefix filled in.
Can I look up many MAC addresses at once?
Yes — switch to Batch mode, paste or drop a file with one MAC address per line, and export the results as CSV.
What MAC address formats does it accept?
Any punctuation works — colons, hyphens, Cisco dot notation, or no separator at all — as long as 12 hex digits remain once it's stripped.
Why doesn't my phone's MAC match its expected vendor?
Many modern devices randomize their MAC address for privacy, generating a locally-administered address with no real vendor registration.
Is my MAC address sent anywhere?
No, lookup runs against a local dataset in your browser.
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