MAC Address Validator and Analyzer
Paste a MAC address in colon, hyphen, dot or bare hex form to validate it. The analyzer normalizes it to colon-separated lowercase and decodes the first octet to tell you whether it is unicast or multicast, universally or locally administered, plus the OUI prefix.
How to validate a MAC address
- Paste a MAC address such as aa:bb:cc:dd:ee:ff, AA-BB-CC-DD-EE-FF or aabb.ccdd.eeff.
- Read the valid or invalid indicator and the normalized colon form.
- Check whether it is unicast or multicast, universal or local, and view the OUI.
Examples
Cisco dot notation
aabb.ccdd.eeff
aa:bb:cc:dd:ee:ff
A multicast address
01:00:5e:00:00:01
multicast, OUI 01:00:5e
Frequently asked questions
Which MAC address formats are accepted?
Four common notations: colon-separated (aa:bb:cc:dd:ee:ff), hyphen-separated (aa-bb-cc-dd-ee-ff), Cisco dotted groups of four (aabb.ccdd.eeff) and 12 bare hex digits (aabbccddeeff). Whatever you paste is normalized to colon-separated lowercase.
What is the difference between a unicast and a multicast MAC?
It is the least-significant bit of the first octet, the I/G bit. When it is 0 the address is unicast and identifies a single interface. When it is 1 the address is multicast and targets a group of receivers, like 01:00:5e for IPv4 multicast.
What does universally versus locally administered mean?
It is the second-least-significant bit of the first octet, the U/L bit. A 0 means the address was assigned by the manufacturer from its OUI block (universal). A 1 means it was set locally, for example by virtualization or a randomized device address.
What is the OUI?
The Organizationally Unique Identifier is the first three octets of a MAC address. The IEEE assigns each block to a manufacturer, so the OUI usually identifies the maker of the network hardware. This tool shows the OUI so you can look it up in a vendor database.
Is the MAC address I paste sent anywhere?
No. Validation and analysis run entirely in your browser, so the address never leaves your device and nothing is uploaded.
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