MAC Address Lookup

Q: What is a MAC address and why does every device have one?

A MAC address is a unique 48-bit hardware identifier permanently assigned to a network interface by its manufacturer. Unlike an IP address, which is assigned dynamically, a MAC address is intended to be a permanent identifier tied to the physical hardware.

Q: What is an OUI and how does this lookup work?

The first three octets of a MAC address form the OUI, an Organizationally Unique Identifier the IEEE assigns to hardware manufacturers. This tool extracts the OUI from your input and queries the IEEE registry to return the registered manufacturer name.

Q: What do the Unicast/Multicast and UAA/LAA bits mean?

The first octet contains two flag bits. The I/G bit indicates whether a frame targets one device (unicast) or a group (multicast). The U/L bit indicates whether the address was assigned by the manufacturer (Universally Administered) or configured locally by software (Locally Administered).

Q: Can I find a device's location from its MAC address?

No. A MAC address only reveals the manufacturer. It operates within a local network segment and is stripped once traffic crosses a router, so it cannot expose geographic location.

Enter any MAC address or 6-character OUI prefix to instantly identify the device manufacturer, vendor and IEEE registration details — no sign-up needed.

Accepts any format: 00:1A:2B:3C:4D:5E · 00-1A-2B-3C-4D-5E · 001A2B3C4D5E · or just the OUI prefix 001A2B

Try a quick example

Apple 00:1A:2B Intel 00:1B:21 Samsung 00:1C:62 Cisco 00:0C:F1 Google 54:60:09 Raspberry Pi B8:27:EB

Vendor identified for B8:27:EB

Raspberry Pi Foundation

Identified Device Vendor

B8:27:EB

OUI: B8:27:EB

Vendor

Raspberry Pi Foundation

OUI Prefix

B8:27:EB

Standard

EUI-48 (IEEE 802)

Registry

IEEE MA-L (OUI Large)

Frame Type

Unicast

Assignment

Globally Unique (UAA)

Reset

MAC Address Structure

OUI — Vendor Prefix

B8:27:EB

Bits 1–24 · IEEE assigned

NIC — Device Suffix

XX:XX:XX

Bits 25–48 · Vendor assigned

Unicast Globally Unique (UAA)

The first 3 octets form the OUI (Organizationally Unique Identifier), registered by IEEE to the manufacturer — here identified as Raspberry Pi Foundation. The remaining 3 octets are the NIC-specific portion, assigned by the manufacturer to uniquely identify this individual hardware interface. Together all 6 octets form a globally unique 48-bit EUI-48 identifier.

Full Lookup Details

Show

MAC (Colon)

B8:27:EB

MAC (Dash)

B8-27-EB

MAC (Plain)

B827EB

OUI Hex

B8:27:EB

NIC Portion

XX:XX:XX

Vendor

Raspberry Pi Foundation

IEEE Registry

MA-L (OUI Large)

Addr Length

48-bit (EUI-48)

Frame Type

Unicast

U/L Bit

Globally Unique (UAA)

Standard

IEEE 802 (Ethernet / Wi-Fi)

First Octet

0xB8 (decimal 184)

Not stored or logged

Real-time IEEE lookup

No sign-up needed

What This Tool Does

This lookup extracts the first six hex characters (the OUI prefix) from any MAC address you enter and queries the IEEE MA-L (MAC Address Large) registry live to return the registered manufacturer name. It supports any common MAC format — colon-separated, dash-separated, or plain hex — and also accepts a bare 6-character OUI prefix without the device-specific NIC suffix. Alongside the vendor name, the tool analyses the first octet's flag bits to show whether the address is unicast or multicast and whether it is globally unique (hardware-assigned) or locally administered (software-assigned).

Vendor Identification

Queries the IEEE OUI database live to return the registered manufacturer name for the first three octets of any MAC address.

Address Structure Analysis

Splits the MAC into OUI and NIC portions and visualises the structure, including the flag bits in the first octet.

Flag Bit Decoding

Identifies whether the address is unicast or multicast (I/G bit) and whether it is hardware-assigned or locally administered (U/L bit).

Multiple Input Formats

Accepts any MAC format: colons, dashes, plain hex, or a bare 6-character OUI prefix. All are normalised automatically before the lookup.

How to Find MAC Addresses on Your Devices

Windows — open Command Prompt and run ipconfig /all. Look for "Physical Address" under each network adapter.
macOS — go to System Settings → Network → select your connection → Details → Hardware tab.
Linux — run ip link show or ifconfig -a in a terminal. The MAC appears as "link/ether".
Android — Settings → About Phone → Status → Wi-Fi MAC address. (Note: modern Android randomises MAC by default.)
iPhone / iPad — Settings → General → About → Wi-Fi Address.
Router admin panel — connected devices list shows the MAC of each device on your local network. Use this lookup to identify unknown devices.
If a MAC returns no vendor result and the U/L bit shows "Locally Administered", the device is using MAC randomisation — a privacy feature that generates a temporary random MAC rather than transmitting the hardware one.

Frequently Asked Questions

What is a MAC address and why does every device have one?

A MAC address (Media Access Control address) is a unique 48-bit hardware identifier permanently assigned to a network interface card by its manufacturer at the factory. Every device that connects to a network — Ethernet adapter, Wi-Fi card, Bluetooth module, or cellular modem — has at least one MAC address burned into its hardware. Unlike an IP address, which is assigned dynamically by a router and can change, a MAC address is intended to be a permanent, globally unique identifier tied to the physical hardware.

MAC addresses operate at Layer 2 of the OSI model and are used by switches and access points to deliver frames to the correct device within a local network segment. Two devices on the same network cannot share the same MAC address without causing connectivity problems, which is why the IEEE assigns globally unique OUI prefixes to each manufacturer.

What is an OUI and how does this lookup work?

The first three octets (24 bits) of every MAC address form the OUI — Organizationally Unique Identifier. The IEEE assigns OUI blocks to hardware manufacturers when they register to produce network hardware. Every device the company makes then begins with their registered OUI prefix, making the manufacturer immediately identifiable from just the first six hex characters.

This tool extracts those six characters and queries the IEEE OUI database live. It works for any Ethernet card, Wi-Fi adapter, router, smartphone, printer or IoT device as long as the OUI is publicly registered. To investigate the network-level ownership of any IP address the device communicates from, use our ASN Lookup.

What input formats are accepted?

This tool accepts any common MAC format: colon-separated (00:1A:2B:3C:4D:5E), dash-separated (00-1A-2B-3C-4D-5E), plain hex (001A2B3C4D5E), or a bare 6-character OUI prefix (001A2B). All separators and capitalisation are normalised automatically before the lookup.

The only requirement is that the cleaned hex string is exactly 6 characters (an OUI-only lookup) or exactly 12 characters (a full MAC address). Anything in between — 7 to 11 characters — is rejected with a clear error message rather than silently guessing. Upper and lower case hex digits are both accepted.

What do the Unicast/Multicast and UAA/LAA bits mean?

The first octet of a MAC address contains two important flag bits. The least-significant bit (I/G bit) indicates addressing type: 0 means the frame targets a single device (unicast), while 1 means it targets a group (multicast or broadcast). Standard device MACs are always unicast.

The second-least-significant bit (U/L bit) indicates assignment authority: 0 means the address was assigned by the IEEE-registered manufacturer (Universally Administered Address — UAA), while 1 means it was configured locally by software (Locally Administered Address — LAA). Many operating systems assign LAA MACs to virtual adapters, VPN interfaces, and randomised Wi-Fi MACs. If you look up an LAA address, the OUI is not from the IEEE registry and will typically return no vendor result.

Can I find a device's location from its MAC address?

No. A MAC address alone reveals only the manufacturer — it cannot expose geographic location. MAC addresses operate exclusively within a local network segment. Once traffic crosses a router onto the internet, the original device's MAC is completely stripped and replaced at each hop. By the time a packet reaches a remote server, the sender's MAC is entirely absent.

To find geographic information about a network connection, you need the public IP address and our IP Geolocation tool. The MAC address and IP address operate at different layers of the network stack and serve completely different purposes — MAC addresses are for local delivery, IP addresses are for internet-wide routing.

What is MAC address randomisation and why does it affect lookups?

Modern smartphones and laptops increasingly use MAC address randomisation as a privacy protection. When scanning for Wi-Fi or joining a new network, the device generates a random locally administered MAC instead of its permanent hardware MAC, preventing location tracking across venues. iOS (since version 14), Android (since version 10) and Windows 10/11 all support MAC randomisation on Wi-Fi by default.

A randomised MAC always has the U/L bit set to 1 (locally administered) and its OUI does not match any IEEE-registered manufacturer — lookups typically return no vendor result. The permanent hardware MAC is still visible in the device's own network settings if you need it for comparison. The "Locally Administered" flag in the Assignment field of this tool's results is the reliable indicator that randomisation is in use.

Why did my lookup say the vendor service is temporarily busy?

This tool queries the IEEE OUI database via a third-party API that applies its own request limits to keep access fair across all users. If a burst of lookups happens in quick succession, the upstream service may briefly decline new requests. This message is intentionally kept separate from a genuine "vendor not found" result — the two have completely different causes.

A temporary busy message means simply waiting a few seconds and retrying; a "not found" result means the OUI itself is not in the public registry, is privately assigned, is a locally administered address, or belongs to a manufacturer that registered privately rather than publicly. Private OUI registrations are common in large enterprises that need large numbers of MAC addresses but do not want their hardware publicly identifiable.

How does a MAC address relate to an IP address?

A MAC address and an IP address work at different network layers and serve complementary roles. The MAC address identifies physical hardware and is used within a local network segment at Layer 2 (Data Link). The IP address identifies logical network location and routes traffic between different networks at Layer 3 (Network). ARP (Address Resolution Protocol) bridges the two layers — when a device wants to send data to another on the same local network, it uses ARP to discover which MAC address corresponds to the target IP.

Once traffic leaves through a router, MAC addressing is entirely replaced at each hop while only the IP address travels end to end. This is why your router's MAC address, not your device's MAC address, is what any external server sees at the Ethernet layer. For subnet-level networking calculations, use our Subnet Calculator.

What are common uses for MAC address lookups in network administration?

Identifying unknown devices on a local network is the most common use case. When a new device appears on a router's ARP table, DHCP lease list, or switch port table, a MAC lookup instantly identifies the manufacturer — confirming whether it is a legitimate device or a potential intruder. Security teams use MAC lookups as a first triage step when investigating suspicious network activity.

Access control lists on wireless access points use MAC filtering to restrict which devices can connect, and OUI lookups help classify hardware before adding it to an allowed list. For a complete network investigation, combine MAC lookup results with WHOIS data, DNS records and IP geolocation to build a full picture of what a device is and where it is connecting from.