MAC Address Lookup

Find the vendor, OUI manufacturer, address type, and local/vendor administration flags for any MAC address.

Supports: 00:1A:2B:3C:4D:5E · 00-1A-2B-3C-4D-5E · 001A.2B3C.4D5E · 001A2B3C4D5E

How MAC Address Lookup Works

A MAC address is a link-layer identifier. For an EUI-48 created from an IEEE MA-L assignment, the first 24 bits are the OUI; locally administered addresses do not carry an authoritative vendor prefix.

This tool reports the organization registered for a matching MA-L assignment. A match is useful inventory context, but it does not prove who manufactured, sold, or currently owns a particular device.

The bundled snapshot contains 39,762 distinct MA-L assignments from 39,765 rows in the official IEEE CSV, retrieved 2026-07-17. It covers MA-L only—not MA-M, MA-S, IAB, CID, or locally administered addresses.

If you need new test data instead of identifying existing hardware, use the random MAC address generator to create fake, dummy, local, or vendor MAC addresses. For deeper background, read the MAC address guide or the OUI manufacturer guide.

Common Use Cases

  • Identify unknown devices on your network
  • Network inventory and asset management
  • Security auditing and intrusion detection
  • Troubleshooting connectivity issues
  • Verify hardware manufacturer claims

Address Anatomy

  • Octets 1–3: OUI (manufacturer identifier)
  • Octets 4–6: NIC-specific (device unique)
  • Bit 0 of Octet 1: Unicast (0) / Multicast (1)
  • Bit 1 of Octet 1: UAA (0) / LAA (1)

Verifiable First-Octet Examples

00 (00000000) is individual/universal; 01 (00000001) is group/universal; 02 (00000010) is individual/local; and 03 (00000011) is group/local. The least-significant bit is IEEE's I/G flag; the next bit is U/L.

Primary source: IEEE Guidelines for Use of EUI, OUI, and CID. Snapshot method: validate each MA-L CSV row and six-digit assignment, group repeated legacy assignments, sort by assignment, and omit postal addresses. Source SHA-256: e34c59782a69b3955c49174a4a94cd9d10b868674d0f1a40e7d3d5a75baed83c.

See also local vs universal addresses and MAC address formats.

Frequently Asked Questions

What is a MAC address lookup?
This lookup checks the first three octets against the IEEE Registration Authority MA-L public listing. A match names the organization associated with that 24-bit assignment; it does not prove the maker or current owner of a particular device.
What is an OUI (Organizationally Unique Identifier)?
An OUI is a 24-bit IEEE Registration Authority assignment included in an MA-L block. An EUI-48 created from that OUI begins with those three octets. This tool intentionally covers MA-L only, not the separate MA-M, MA-S, IAB, or CID registries.
What does unicast vs multicast mean?
The least significant bit of the first octet determines the type. If it's 0, the address is unicast (destined for a single device). If it's 1, it's multicast (destined for a group of devices). Real network interfaces almost always use unicast addresses.
What does UAA vs LAA mean?
UAA (Universally Administered Address) means the MAC was assigned by the manufacturer using their IEEE-registered OUI. LAA (Locally Administered Address) means the MAC was manually set or randomized by software. The second bit of the first octet indicates this: 0 = UAA, 1 = LAA.
How accurate is this MAC address lookup?
The bundled snapshot contains 39,762 distinct MA-L assignments from the official IEEE CSV retrieved on 2026-07-17. A match reports the registered organization for that assignment, not verified device provenance. Locally administered addresses do not encode an IEEE-assigned vendor prefix.
Why does a lookup show "Locally Administered Address"?
A locally administered MAC address was set by software instead of assigned by a hardware vendor. It is common with randomized Wi-Fi addresses, virtual machines, containers, VPN adapters, and generated test data. If you need one for development, use the random MAC address generator and choose Local administration.
Can I look up any MAC address?
Yes. Enter any valid MAC address in any common format (colon-separated, hyphen-separated, Cisco dot notation, or plain hex). The tool will parse it, identify the vendor, and show you a full breakdown including binary representation.
Where do I find my device's MAC address?
On Windows, run ipconfig /all in Command Prompt. On macOS/Linux, run ifconfig or ip link in Terminal. On smartphones, check Settings → About → Wi-Fi MAC Address. Routers typically show connected device MACs in their admin panel.
Is my MAC address sent to your server?
No. This tool runs 100% in your browser. The OUI database is downloaded once and cached locally. Your MAC address never leaves your device — we can't see it, log it, or store it.

Related Tools and Guides

MAC Address Generator

Generate random MAC addresses with custom format, vendor prefix, and bulk export options.

OUI Manufacturer Guide

Learn how vendor prefixes identify hardware manufacturers and why some addresses have no vendor.

Find Your MAC Address

Get the MAC address from Windows, macOS, Linux, iPhone, Android, routers, and network tools.

Quick Reference

MAC Format

XX:XX:XX:YY:YY:YY

XX = OUI (vendor) · YY = NIC-specific

First Octet Flags

Bit 0 = 0: Unicast · 1: Multicast

Bit 1 = 0: UAA · 1: LAA

Total Address Space

248 = 281,474,976,710,656

Unique MAC addresses possible

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