MAC Address Generator
Random locally administered MAC addresses, plus a MAC checker.
About this tool
Choose how many addresses you need, the format and an optional OUI prefix, then copy the list. Below, paste any MAC address to see it in every format, whether it is unicast or multicast, whether it is universally or locally administered, and its OUI.
What the bits in a MAC address mean
A MAC address is 48 bits, written as six bytes. Two bits of the first byte matter. The lowest bit is the I/G bit: 0 means unicast (one device) and 1 means multicast or broadcast. The second-lowest is the U/L bit: 0 means universally administered, with the first three bytes being an OUI that the IEEE assigned to a manufacturer, and 1 means locally administered, set by software. That's why locally administered unicast addresses always have 2, 6, A or E as their second hex digit, and why they're the safe choice for virtual machines, containers, test networks and sample data: they can never collide with real hardware. Modern phones and laptops use random locally administered MACs on Wi-Fi for privacy. Hypervisors and vendors use their own OUI prefixes, which you can enter. Formats differ by system: colons (Linux, macOS), hyphens (Windows) and dotted groups of four (Cisco). Honest limits: random generation uses the browser's secure generator, but it can't check for duplicates on your network. Vendor lookup needs the IEEE registry, which isn't bundled here. The UUID decoder, IP range to CIDR and the subnet calculator are related.
Frequently asked questions
What is a locally administered MAC address?
One whose second-lowest bit of the first byte is set (second hex digit 2, 6, A or E), meaning software assigned it.
Can I use a random MAC address for a VM?
Yes. Use a locally administered unicast address so it can't clash with real hardware.
How do I tell if a MAC is multicast?
If the lowest bit of the first byte is 1 (an odd first byte), it's multicast.
Is anything uploaded?
No. Everything runs in your browser and nothing is stored or sent.