Free tool
Random MAC address generator
Everything below runs in your browser: nothing you generate here is sent to macadress.com. Pick unicast or multicast, universal or local administration, or start from a real registered vendor prefix and randomize only the device bits.
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Nothing generated yet.
What "random" here actually means
Every address is built with the browser's own cryptographic random number source (crypto.getRandomValues), not a weaker general-purpose one, so batches don't collide or fall into a predictable pattern. The only bits this tool ever fixes on purpose are the I/G and U/L flags in the first octet, plus, if you pick a vendor, that vendor's real registered prefix; every other bit is random.
Unicast, multicast, universal, local
The first octet of a MAC address carries two flags. The low bit (I/G) is 0 for a normal device address (unicast) or 1 for a group address (multicast) that many interfaces can accept at once. The next bit (U/L) is 0 for a universally administered address, one IEEE assigned to a real manufacturer's block, or 1 for a locally administered one, set by software rather than burned into hardware. See how MAC addresses are structured for the full bit layout, including the IEEE 802c SLAP quadrants inside the local space.
When "universal" isn't a real vendor
Clearing the U/L bit without picking a vendor above produces an address that is shaped like a factory-assigned one but isn't registered to anybody: fine for tests, fixtures, and documentation, but it won't resolve to a real organization if you look it up. Pick a vendor from the search box to fix a prefix IEEE actually assigned, and randomize only the remaining device bits, or paste the result into the lookup tool to see exactly how it's classified.
Before you use a generated address on real hardware
A random or spoofed MAC address can collide with another device on the same network segment, and changing a network interface's address is against the terms of service on some networks. This tool is for testing, fixtures, and documentation, not for evading a MAC-based access control you don't control. If you need addresses for provisioning real devices at volume, you need an assignment of your own, not randomly generated ones.