Work out mac oui lookup format instantly with clear inputs, formula shown and shareable results.
A 48-bit MAC splits into a 24-bit Organisationally Unique Identifier assigned by the IEEE and a 24-bit device-specific part. The two low bits of the first byte are flags: bit 0 set means a group address, and bit 1 set means locally administered, which is what randomised Wi-Fi privacy addresses and virtual interfaces use. Vendors, switches and scripts all render the same bytes differently, hence the format options.
MAC structure
bytes 1-3 = OUI, bytes 4-6 = NIC specific; bit0 of byte1 = individual/group, bit1 = universal/local
Modern devices generate locally administered random MACs per SSID for privacy, which you can spot because bit 1 of the first byte is set.
Only by looking the OUI up in the IEEE registry. The address itself carries no vendor name, just the assigned 24-bit prefix.