MAC Address Lookup
Paste a MAC address in any format to get the vendor from all 58,000+ IEEE assignments, its block size, whether it is randomized or multicast, and its other formats — in your browser, with nothing sent anywhere.
Use the MAC Address Lookup
MAC Address
Try an example
Lists every MA-L, MA-M and MA-S prefix registered to matching organizations.
IEEE registry: 58,748 assignments (9 Oct 2026). Loads on first lookup, about 0.5 MB.
Lookup Result
Manufacturer / organization
—
- Normalized
- Matched prefix
- Address type (I/G bit)
- Scope (U/L bit)
- First byte
Other formats
Batch Results
| # | MAC Address | Prefix | Vendor | Type |
|---|
Prefixes by Organization
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Enter a MAC address on the left and click Look Up.
How to Read the First Byte: Randomized, Multicast or Vendor-Assigned
The two lowest bits of the first byte decide what kind of address it is. The quickest check is the second hex digit.
| Second hex digit | U/L bit | I/G bit | Meaning | Vendor lookup? |
|---|---|---|---|---|
| 0, 4, 8, C | 0 | 0 | Globally unique unicast (burned-in by the manufacturer) | Yes — IEEE registry |
| 2, 6, A, E | 1 | 0 | Locally administered unicast: randomized/private Wi-Fi MACs, VMs, containers, bonded links | No — set by software |
| 1, 5, 9, D | 0 | 1 | Globally assigned multicast / group address (e.g. 01:80:C2…, 01:00:5E…) | Protocol, not a device |
| 3, 7, B, F | 1 | 1 | Locally administered multicast (33:33… IPv6, FF:FF… broadcast) | Protocol, not a device |
Special-Purpose MAC Addresses
These addresses identify a protocol or virtual router, not a hardware vendor. The lookup above recognises all of them.
| Address / range | Used for | Notes |
|---|---|---|
| FF:FF:FF:FF:FF:FF | Broadcast | Every host on the LAN segment (ARP requests, DHCP discover). |
| 01:00:5E:00:00:00 – 01:00:5E:7F:FF:FF | IPv4 multicast | Low 23 bits of the 224.0.0.0/4 group address (RFC 1112). |
| 33:33:xx:xx:xx:xx | IPv6 multicast | Last 32 bits of the ff00::/8 group address (RFC 2464). |
| 01:80:C2:00:00:00 | Spanning Tree (STP/RSTP/MSTP) | IEEE 802.1D bridge group address; never forwarded by bridges. |
| 01:80:C2:00:00:01 | Ethernet PAUSE (flow control) | IEEE 802.3x MAC control frames. |
| 01:80:C2:00:00:02 | Slow protocols: LACP, OAM | IEEE 802.3 link aggregation and link OAM. |
| 01:80:C2:00:00:0E | LLDP | IEEE 802.1AB nearest-bridge address, also used by PTP over Ethernet. |
| 01:00:0C:CC:CC:CC | Cisco CDP, VTP, DTP, UDLD | Cisco proprietary discovery and trunking protocols. |
| 01:00:0C:CC:CC:CD | Cisco PVST+ | Per-VLAN Spanning Tree Plus BPDUs. |
| 00:00:5E:00:01:xx | VRRP (IPv4) virtual router | xx = virtual router ID (RFC 5798). |
| 00:00:5E:00:02:xx | VRRP (IPv6) virtual router | xx = virtual router ID (RFC 5798). |
| 00:00:0C:07:AC:xx | Cisco HSRP v1 virtual MAC | xx = HSRP group (0–255). |
| 00:00:0C:9F:F0:00 – 00:00:0C:9F:FF:FF | Cisco HSRP v2 virtual MAC | Last 12 bits = HSRP group (0–4095). |
| 52:54:00:xx:xx:xx | QEMU / KVM / libvirt default | Locally administered; not an IEEE assignment. |
| 02:42:xx:xx:xx:xx | Docker default bridge | Locally administered; container interfaces. |
IEEE Block Sizes and Data Source
- MA-L (MAC Address Block Large, the classic OUI): 24-bit prefix, 224 ≈ 16.8 million addresses. Example 00:03:93 → Apple, Inc.
- MA-M (Medium): 28-bit prefix, about 1 million addresses. Example 9C:43:1E:9 → "CONTINENT" Co. Ltd.
- MA-S (Small) and the retired IAB: 36-bit prefix, 4,096 addresses. Example 70:B3:D5:F2:A → WIBOND Informationssysteme GmbH.
- An MA-L listed as "IEEE Registration Authority" (such as 70:B3:D5 or 8C:1F:64) has been split into MA-M or MA-S blocks; only the longer prefix names the real owner.
- "Private" means the owner paid to keep its name out of the public listing.
Source: IEEE Registration Authority public listings MA-L, MA-M, MA-S and IAB, downloaded 9 October 2026. Bit meanings follow IEEE 802-2014 §8.
Summary
The first 24 bits of a globally unique MAC address are an OUI that the IEEE Registration Authority assigns to one organization. Smaller blocks exist too: MA-M assigns 28-bit prefixes and MA-S (and the older IAB) 36-bit prefixes, so many devices can only be identified with more than the first three bytes. This tool loads the complete IEEE MA-L, MA-M, MA-S and IAB listings (58,748 assignments, snapshot 9 October 2026), matches the longest prefix, and explains the two flag bits of the first byte: multicast and locally administered, which is how phones and laptops mark randomized private addresses.
How it works
- Paste a MAC in any notation: 00:1A:2B:3C:4D:5E, 00-1A-2B-3C-4D-5E, 001a.2b3c.4d5e or 001A2B3C4D5E. A bare OUI such as 00:1A:2B also works.
- The tool strips separators and checks the I/G bit (multicast) and U/L bit (locally administered) of the first byte.
- For globally unique addresses it matches the longest IEEE prefix: 36-bit MA-S or IAB, then 28-bit MA-M, then 24-bit MA-L.
- Special-purpose addresses (broadcast, IPv4 and IPv6 multicast, STP, LLDP, VRRP, HSRP, QEMU and Docker defaults) are recognised by pattern.
- Batch mode looks up one MAC per line and exports CSV; vendor search lists every prefix registered to a company.
Use cases
- Identify unknown devices in a router's DHCP client list or ARP table.
- Tell a phone's randomized Wi-Fi address apart from its real hardware address.
- Decode MACs captured in Wireshark or tcpdump, including multicast and protocol addresses.
- Find every OUI a vendor owns to build switch ACLs or NAC device profiles.
- Convert a MAC to Cisco dotted notation or to its IPv6 link-local EUI-64 address.
- Check whether a VM is using a VMware, Hyper-V, VirtualBox or QEMU prefix.