MAC OUI Lookup Format Calculator

Work out mac oui lookup format instantly with clear inputs, formula shown and shareable results.

About MAC OUI Lookup Format Calculator

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.

Formula

MAC structure

bytes 1-3 = OUI, bytes 4-6 = NIC specific; bit0 of byte1 = individual/group, bit1 = universal/local

Worked example

With the default values below, MAC OUI Lookup Format Calculator returns Formatted MAC address of 00:1a:2b:3c:4d:5e. Change any input above and every figure here is recalculated in your browser.

Inputs used

MAC address: 00-1A-2B-3C-4D-5E
Output formatone of Colon separated (00:1a:2b:3c:4d:5e), Hyphen separated (00-1A-2B-3C-4D-5E), Cisco dotted (001a.2b3c.4d5e), Bare hex (001a2b3c4d5e): Colon separated (00:1a:2b:3c:4d:5e)

Results

Formatted MAC address: 00:1a:2b:3c:4d:5e
OUI (first 24 bits): 00:1A:2B
Device identifier (last 24 bits): 3C:4D:5E
Address type flags: Individual / unicast, universally administered (OUI assigned by IEEE)

Step by step

1Values used
2MAC structure
3Formatted MAC address= 00:1a:2b:3c:4d:5e
4OUI (first 24 bits)= 00:1A:2B
5Device identifier (last 24 bits)= 3C:4D:5E
6Address type flags= Individual / unicast, universally administered (OUI assigned by IEEE)

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does my phone show a different MAC on each network?

Modern devices generate locally administered random MACs per SSID for privacy, which you can spot because bit 1 of the first byte is set.

Can I identify a vendor without a database?

Only by looking the OUI up in the IEEE registry. The address itself carries no vendor name, just the assigned 24-bit prefix.