Which company owns MAC address prefix E4:04:39?

MAC address prefix E4:04:39 is registered to TomTom Software Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:04:39 has a network interface built by TomTom Software Ltd.

What is the OUI E4:04:39?

E4:04:39 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TomTom Software Ltd. It covers every address from E4:04:39:00:00:00 to E4:04:39:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-04-39.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in E4:04:39:00:00:00 that is E4:04:39 — 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 TomTom Software Ltd located?

TomTom Software Ltd is listed at 20th Floor Euston Tower London GB NW1 3AS in the IEEE OUI registry entry for E4:04:39. This is the address the organization registered with the IEEE, which may differ from its current operating address.

TomTom Software Ltd

MAC address prefix E4:04:39 is registered to TomTom Software Ltd in the IEEE OUI registry. Any device whose MAC address begins with E4:04:39 has a network interface built by TomTom Software Ltd. 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 E4:04:39:00:00:00 to E4:04:39:FF:FF:FF.

OUI prefix: E4:04:39
Hyphen form: E4-04-39
MAC range: E4:04:39:00:00:00 – E4:04:39:FF:FF:FF
Addresses in block: 16,777,216
Organization: TomTom Software Ltd
Address: 20th Floor Euston Tower London GB NW1 3AS
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.

Assignment history (2)

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

2016-07-29Assigned to "TomTom Software Ltd"
archived source →
2026-07-17Assigned to "TomTom Software Ltd"

Nearby in the registry

The prefixes assigned immediately before and after E4:04:39:

FAQ

Which company owns MAC address prefix E4:04:39?: MAC address prefix E4:04:39 is registered to TomTom Software Ltd in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:04:39 has a network interface built by TomTom Software Ltd.
What is the OUI E4:04:39?: E4:04:39 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to TomTom Software Ltd. It covers every address from E4:04:39:00:00:00 to E4:04:39:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-04-39.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in E4:04:39:00:00:00 that is E4:04:39 — 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 TomTom Software Ltd located?: TomTom Software Ltd is listed at 20th Floor Euston Tower London GB NW1 3AS in the IEEE OUI registry entry for E4:04:39. This is the address the organization registered with the IEEE, which may differ from its current operating address.