About macaddress.net

What is a MAC Address?

A Media Access Control (MAC) address is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. Every device that connects to a network — your phone, laptop, router, smart TV, IoT sensor — has at least one MAC address.

MAC addresses are 48 bits long (6 bytes), typically written as six groups of two hexadecimal digits separated by colons or hyphens:

  • AA:BB:CC:DD:EE:FF (colon-separated)
  • AA-BB-CC-DD-EE-FF (hyphen-separated)
  • AABBCCDDEEFF (raw hex)

What is an OUI?

The first three octets (24 bits) of a MAC address form the Organizationally Unique Identifier (OUI). The IEEE (Institute of Electrical and Electronics Engineers) assigns OUI blocks to manufacturers and organizations.

For example, if a MAC address starts with DC:A6:32, the OUI DCA632 is registered to Raspberry Pi Trading Ltd. This is how we can identify the manufacturer of a device just from its MAC address.

How This Tool Works

macaddress.net performs all lookups entirely in your browser. Here's what happens:

  1. When you use the lookup tool, the IEEE OUI database is downloaded to your browser (a ~1.3 MB JSON file)
  2. When you enter a MAC address, the first 6 hex characters (OUI prefix) are extracted
  3. The OUI is matched against the local database — no server request needed
  4. Results are displayed instantly

The MAC you type is not posted to a lookup API. After a single lookup, the address bar may show only the six-character OUI prefix. See the privacy policy for what the host can log.

OUI Database Source

The database is sourced from the IEEE Standards OUI list. It contains about 40,000 manufacturer prefixes and is refreshed twice a month.

The IEEE MA-L (MAC Address Block Large) registry is the most comprehensive source for OUI-to-vendor mappings available.

Supported Formats

Enter MAC addresses in any common format — we'll auto-detect and parse them:

  • AA:BB:CC:DD:EE:FF
  • AA-BB-CC-DD-EE-FF
  • AABB.CCDD.EEFF
  • AABBCCDDEEFF
  • Partial OUI: AA:BB:CC (first 3 octets only)

Limitations

  • Randomized MAC addresses: Modern devices (iOS 14+, Android 10+, Windows 10+) use random MAC addresses for Wi-Fi scanning. These won't match any vendor.
  • Locally administered addresses: If the second hex digit of the first octet is 2, 3, 6, 7, A, B, E, or F (U/L bit set), the address is locally administered and won't have an OUI match.
  • Virtual interfaces: Hypervisors and virtual machines may use custom MAC ranges.