MAC Address Vendor Lookup

Look up which vendor owns a MAC address from the IEEE OUI (MA-L) registry. Paste one or many MACs in colon, dash, bare or Cisco format. Free, runs entirely in your browser.

Click Look up to resolve vendors.

How to use it

  1. Paste one MAC or a list (new lines or commas). Formats accepted: aa:bb:cc:dd:ee:ff, aa-bb-cc-dd-ee-ff, aabbccddeeff and Cisco aabb.ccdd.eeff.
  2. The first three octets (24-bit OUI) are matched against a static IEEE MA-L snapshot. Results show the organization name, the OUI and address flags (multicast / locally administered).
  3. Up to 100 addresses are processed per lookup. Locally administered addresses (second least-significant bit of the first octet set) are often randomized by privacy features and may not map to a vendor.

Related tools

Also try ASN IP Lookup and DNS Lookup.

FAQ

What is an OUI?

An Organizationally Unique Identifier is the first 24 bits (three octets) of a MAC address assigned by the IEEE to a vendor. Looking up the OUI tells you which organization the adapter was registered to (for universal, factory-assigned addresses).

Which MAC formats are supported?

Colon-separated (aa:bb:cc:dd:ee:ff), hyphen (aa-bb-cc-...), bare hex (aabbccddeeff) and Cisco dotted (aabb.ccdd.eeff). Separators are stripped and the first six hex digits are used as the OUI.

What do locally administered and multicast mean?

In the first octet, bit 0 (least significant) marks multicast/group addresses; bit 1 marks locally administered addresses (set by software, often randomized for privacy). Locally administered MACs usually will not match a vendor OUI.

Why is a vendor unknown?

The OUI may be newer than this page's snapshot, assigned under a longer MA-M/MA-S prefix (this tool uses 24-bit MA-L only), private/locally administered, or unused. Refresh the site after we update the IEEE CSV snapshot.

Is my MAC address uploaded anywhere?

No. The OUI database is loaded as a static JSON file into your browser and matching happens locally. Addresses you paste never leave your machine.

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