MAC address lookup
Validate and format MAC addresses: parse the OUI (first 3 bytes) against a built-in offline vendor table, detect locally administered and multicast bits, and output aa:bb:cc:dd:ee:ff, aa-bb-…, aabb.ccdd.eeff and AABBCCDDEEFF — with batch lookups. The vendor table is a partial built-in dataset and is not exhaustive or up to date.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Accepts 12 hex digits, with : - . or spaces as separators; a 0x prefix is ignored.
Result
00:1b:63:84:45:e6
Apple, Inc.001b638445e600:1b:63:84:45:e600-1b-63-84-45-e6001b.6384.45e6001B638445E6001B.6384.45E6NoNoNoNoWhat this tool does
- See which vendor made the NIC behind a MAC you spotted in a router, switch or packet capture: the built-in offline OUI table resolves it.
- Normalise the notation: one hex string yields colon, hyphen, Cisco dotted (001b.6384.45e6), plain uppercase and dotted uppercase forms, ready to paste into different device configs.
- Classify the address: locally administered, multicast, all-F broadcast or all-zero — the flags that decide how switches treat it.
- Work through a list: paste one MAC per line (lines starting with # are treated as comments) and get valid/invalid rows, unknown-vendor counts and standard notations in one pass.
Example
Input
00:1B:63:84:45:E6
Output
OUI prefix: 001b63 NIC part: 8445e6 Vendor: Apple, Inc. Flags: not locally administered, not multicast Colon separated: 00:1b:63:84:45:e6 Hyphen separated: 00-1b-63-84-45-e6 Cisco notation: 001b.6384.45e6 Plain (upper case): 001B638445E6
Input is lowercased and stripped of separators, so case and separator style do not matter. Vendor data comes from a bundled offline table with no network lookup.
Frequently asked questions
Why is no vendor found for my MAC?
Three common causes: it is a locally administered address (bit 1 of the first octet set, such as 02:42:AC:…), and randomised MAC prefixes belong to no registered vendor; it is a software-generated address for a VM or container NIC; or the vendor is simply not in the built-in selection of common prefixes.
What input formats are accepted?
After removing : - . spaces and a 0x prefix, exactly 12 hex digits are required. A wrong length reports a length error and non-hex characters report an invalid-address error. In batch mode, blank lines and lines starting with # are skipped.
What do locally administered and multicast mean?
The low bit of the first octet is the multicast bit: 1 means a multicast (or broadcast) address that every device in the broadcast domain listens for. The second-low bit is the locally administered bit: 1 means the address was assigned locally (randomised MACs, virtual NICs) rather than being a globally unique IEEE registration.
Does the vendor lookup use the network?
No. The vendor table ships with the page and matching is local. The trade-off is that it is a selection and never auto-updates, so check the public IEEE OUI listing when something is missing.
Can this locate the device?
No. A MAC only reveals the NIC vendor — no geography, no device model. It can tell you whether something looks like a phone, a router or a VM, and that is the extent of it.
Keywords：mac addressmac 地址oui厂商vendor网卡aa:bb:cccisco 写法本地管理组播