Which company owns MAC address prefix FC:91:5D?

MAC address prefix FC:91:5D is registered to Google, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with FC:91:5D has a network interface built by Google, Inc..

What is the OUI FC:91:5D?

FC:91:5D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Google, Inc.. It covers every address from FC:91:5D:00:00:00 to FC:91:5D:FF:FF:FF, or 16,777,216 addresses in total. It is also written FC-91-5D.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in FC:91:5D:00:00:00 that is FC:91:5D — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is Google, Inc. located?

Google, Inc. is listed at 1600 Amphitheatre Parkway Mountain View CA US 94043 in the IEEE OUI registry entry for FC:91:5D. This is the address the organization registered with the IEEE, which may differ from its current operating address.

How many MAC prefixes does Google, Inc. own?

Google, Inc. holds 110 OUI prefixes in the IEEE registry, of which FC:91:5D is one. A device made by Google, Inc. could carry a MAC address from any of them.

Google, Inc.

MAC address prefix FC:91:5D is registered to Google, Inc. in the IEEE OUI registry. Any device whose MAC address begins with FC:91:5D has a network interface built by Google, Inc.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from FC:91:5D:00:00:00 to FC:91:5D:FF:FF:FF.

OUI prefix: FC:91:5D
Hyphen form: FC-91-5D
MAC range: FC:91:5D:00:00:00 – FC:91:5D:FF:FF:FF
Addresses in block: 16,777,216
Organization: Google, Inc.
Address: 1600 Amphitheatre Parkway Mountain View CA US 94043
Source: IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.

Other prefixes from Google, Inc.

Google, Inc. holds 110 OUI prefixes in total. A device with this exact prefix could just as well carry any of these:

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2024-04-16Assigned to "Google, Inc."
archived source →
2026-07-17Assigned to "Google, Inc."

Nearby in the registry

The prefixes assigned immediately before and after FC:91:5D:

FAQ

Which company owns MAC address prefix FC:91:5D?: MAC address prefix FC:91:5D is registered to Google, Inc. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with FC:91:5D has a network interface built by Google, Inc..
What is the OUI FC:91:5D?: FC:91:5D is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Google, Inc.. It covers every address from FC:91:5D:00:00:00 to FC:91:5D:FF:FF:FF, or 16,777,216 addresses in total. It is also written FC-91-5D.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in FC:91:5D:00:00:00 that is FC:91:5D — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is Google, Inc. located?: Google, Inc. is listed at 1600 Amphitheatre Parkway Mountain View CA US 94043 in the IEEE OUI registry entry for FC:91:5D. This is the address the organization registered with the IEEE, which may differ from its current operating address.
How many MAC prefixes does Google, Inc. own?: Google, Inc. holds 110 OUI prefixes in the IEEE registry, of which FC:91:5D is one. A device made by Google, Inc. could carry a MAC address from any of them.