MAC Address Lookup

Vendor lookup, bulk decoding and MAC ↔ IPv6 conversion, entirely in your browser.

MAC Address Lookup: bulk vendor lookup, decoding and MAC ↔ IPv6

Paste a single MAC address, a list, or raw output from a router or switch. Every address is resolved to its manufacturer against the full IEEE registry and decoded down to the bits: locally, with nothing uploaded.

  • Paste device output directlyarp -a from Linux, Windows or macOS, ip neigh, DHCP leases, or a Cisco, Arista or Juniper MAC address table. Every address on every line is resolved, IP and VLAN columns kept alongside.
  • Full IEEE registryMA-L, MA-M, MA-S, IAB and CID blocks matched longest-prefix-first, with vendor and country.
  • MAC ↔ IPv6 (EUI-64)derive the interface identifier, link-local and SLAAC address from a MAC, or pull the MAC back out of an IPv6 address.
  • Randomized-MAC detectiontells a privacy-randomized phone address apart from real hardware, and flags hypervisor and virtual-NIC ranges.
  • Well-known addresses namedSTP, LLDP, LACP, CDP, PVST+, HSRP and VRRP group numbers, IPv4/IPv6 multicast groups.
  • Nothing leaves your browserthe registry ships as a static asset and every lookup runs client-side, no upload, no rate limit.

Part of the same toolkit as the IPv4 & IPv6 subnet calculator and the data unit converter.

MAC address lookup

Paste anything containing MAC addresses, a single address, a list, an arp -a dump, or a switch MAC address table from Cisco, Arista or Juniper. Every address is resolved to its manufacturer and decoded down to the bits, including randomized-MAC and virtual-interface detection.

Results
4 addresses · 3 vendors · 1 randomized · 1 virtual
MAC addressVendorRegistryType
3C:22:FB:11:22:33Apple, Inc.USMA-LUnicastGlobal
B8:27:EB:12:34:56Raspberry Pi FoundationUSMA-LUnicastGlobal
00:50:56:12:34:56VMware, Inc.USMA-LUnicastVirtual
7A:3B:5C:1D:2E:4FNo vendor, randomized-UnicastRandomized

Resolved against 58,634 IEEE assignments · registry snapshot 2026-09-07

MAC address lookup: find the vendor behind any hardware address

This free MAC address lookup tool identifies the manufacturer of any network interface from its MAC address, and decodes everything else the address encodes along the way. Paste a single address or thousands, in any notation, and this MAC vendor lookup returns the registered organization, the IEEE registry block, the country of registration, and a full bit-level breakdown: instantly, in your browser, with no upload and no signup. The entire IEEE OUI database is loaded client-side, so every lookup after the first is immediate.

Bulk MAC lookup from real device output

Most OUI lookup sites make you paste one address at a time. This one accepts whole dumps: arp -a from Linux, Windows or macOS, ip neigh output, a Cisco or Arista show mac address-table, a Juniper ethernet-switching table, or a DHCP lease file. It finds every MAC address on every line, keeps the IP, VLAN, interface and entry-state columns alongside it, removes duplicates, and tells you which format it detected. Export the resolved list to CSV or JSON when you're done. The workflow network admins actually have, rather than one address at a time.

Randomized MAC address detection

iOS, Android, Windows and modern Linux all randomize MAC addresses by default now, which is why so many lookups come back empty. Instead of showing nothing, this tool detects the signature (the locally-administered bit set with no matching IEEE assignment) and says so plainly. A randomized MAC belongs to the device's privacy feature rather than to any manufacturer, and it typically changes each time the device joins a network, so it can't be used for allow-lists or DHCP reservations. Knowing that is usually more useful than a vendor name would have been.

MAC to IPv6 and EUI-64 conversion

A MAC address deterministically produces an IPv6 interface identifier: split it in half, insert FF:FE, and flip the universal/local bit. This EUI-64 calculator does that conversion in both directions. Enter a MAC to get its IPv6 link-local address and its SLAAC address under any prefix, or paste an IPv6 address to extract the hardware address embedded in it. It's the operation engineers most often do by hand and most often get backwards, and almost no other MAC lookup tool offers it.

Rich decoding beyond the vendor name

Every address is decoded down to the bits. You get unicast versus multicast from the I/G bit, universally versus locally administered from the U/L bit, and the exact IEEE registry block (MA-L (24-bit OUI), MA-M (28-bit), MA-S (36-bit OUI-36), IAB or CID) with the number of addresses that assignment covers. Because assignments are resolved longest-prefix first, addresses inside a subdivided block resolve to the real assignee instead of the IEEE placeholder that shorter matches would return. Well-known addresses are named too: broadcast, STP and LLDP, LACP, Cisco CDP and PVST+, HSRP and VRRP virtual MACs with their group numbers, and IPv4 and IPv6 multicast addresses with the group they carry. Hypervisor prefixes for VMware, Hyper-V, VirtualBox, KVM, Xen, Parallels and Docker are flagged so a virtual NIC is never mistaken for physical hardware.

Every MAC address format accepted

Notation never matters. Colon-separated (00:1A:2B:3C:4D:5E), hyphen-separated (00-1A-2B-3C-4D-5E), Cisco dotted (001A.2B3C.4D5E), bare hex (001a2b3c4d5e), mixed case, and the macOS style that drops leading zeros (0:1a:2b:3:4d:5e) all parse. The tool shows every canonical form back, so it doubles as a MAC address format converter when you need to paste an address into a device that only accepts one notation.

Private by design

The addresses you paste never leave your device. The IEEE registry is downloaded once as a static file and every lookup runs locally against it, so this MAC address vendor lookup works offline once loaded, returns results with no network round-trip, and never logs what you searched for. For anyone auditing a production network, that's a meaningful difference from tools that send each address to a server. And when the same session turns from hardware to addressing, the companion subnet calculator, access list matcher and data unit converter work the same private, in-browser way.

MAC address questions, answered

What is a MAC address?

A MAC (Media Access Control) address is a 48-bit identifier assigned to a network interface, used to deliver frames on the local network segment. It is normally written as six pairs of hexadecimal digits, such as 00:1A:2B:3C:4D:5E.

The first three bytes are the OUI (Organizationally Unique Identifier), which the IEEE assigns to a manufacturer; the remaining bytes identify the individual interface. Unlike an IP address, a MAC address is not routable. It is only meaningful within a single broadcast domain.

How do I find the manufacturer of a MAC address?

Look up the first three bytes (the OUI) in the IEEE registry. Paste any MAC address into the tool and it returns the registered organization, the country of registration and the registry block, resolved locally against the full IEEE database.

Bear in mind that the OUI identifies the company that registered the address block, which is often the chipset or module maker rather than the brand on the finished product. A laptop's Wi-Fi adapter frequently resolves to Intel or Qualcomm rather than the laptop's brand.

Why does my MAC address lookup return no vendor?

The most common reason is MAC randomization. iOS, Android, Windows and modern Linux generate a private, locally-administered address per network by default, and those are not registered to anyone. So no vendor exists to find. The tool detects this and tells you explicitly rather than showing an empty result.

The other possibilities are a spoofed or manually configured address, a very recent assignment not yet in the registry snapshot, or a virtual interface created by a hypervisor. Hypervisor prefixes are recognised and labelled separately.

What is a randomized or private MAC address?

A randomized MAC address is one the operating system generates itself instead of using the interface's burned-in address, so the device cannot be tracked across networks by its hardware identifier. You can recognise one by the universal/local bit: the second-least significant bit of the first byte is set, which makes the second hex digit 2, 6, A or E.

Because these addresses are typically regenerated per network (and on some platforms periodically) they are unsuitable for MAC-based allow-lists, DHCP reservations or captive portal identification.

What is the difference between MA-L, MA-M and MA-S?

They are IEEE assignment sizes. An MA-L gives the holder a 24-bit prefix and the 16,777,216 addresses beneath it. This is what people usually mean by "an OUI". An MA-M is a 28-bit prefix covering 1,048,576 addresses, and an MA-S (also called OUI-36) is a 36-bit prefix covering 4,096 addresses.

Smaller blocks are subdivisions of a 24-bit prefix that IEEE registers to itself, so a lookup that only checks 24 bits will report "IEEE Registration Authority" instead of the real assignee. This tool always matches the longest assignment first. IAB is the retired predecessor of MA-S, and CID is a company ID used for locally-administered addresses that are never globally unique.

How do I convert a MAC address to an IPv6 address?

Use modified EUI-64: split the 48-bit MAC in half, insert FF:FE between the halves to make 64 bits, then flip the universal/local bit (bit 1 of the first byte). Prefix the result with fe80::/64 for the link-local address, or with any /64 prefix for a SLAAC address.

For example 00:1A:2B:3C:4D:5E becomes fe80::21a:2bff:fe3c:4d5e. Note the first byte changing from 00 to 02 because of the bit flip. The tool does this in both directions, including extracting a MAC back out of an EUI-64 address.

Can I look up many MAC addresses at once?

Yes. Paste an entire arp -a dump, a switch MAC address table from Cisco, Arista or Juniper, ip neigh output, a DHCP lease file, or just a list of addresses, and every address on every line is resolved at once.

Duplicates are merged, the IP, VLAN, interface and state columns are kept alongside each address, and lines with no MAC are listed separately so nothing is silently dropped. Results export to CSV or JSON.

What does the first octet of a MAC address tell you?

Its two lowest bits carry flags. The least-significant bit is the I/G bit: 0 means the frame is for a single interface (unicast) and 1 means it is a group address (multicast), FF:FF:FF:FF:FF:FF being the broadcast address.

The next bit is the U/L bit: 0 means universally administered (a real IEEE-assigned address burned into the hardware) and 1 means locally administered, which covers randomized privacy addresses, manually set addresses, and many virtual machine interfaces.

Is this MAC address lookup private?

Yes. The IEEE registry is downloaded once as a static file and every lookup runs against it locally in your browser. Nothing you paste is transmitted anywhere, no query is logged, and the tool keeps working offline once the page has loaded.