Random MAC Address Generator

Generate valid random MAC addresses in any common notation — colon (01:23:45:67:89:ab), hyphen, Cisco dotted (0123.4567.89ab), or no separator — in upper or lowercase. Useful for test fixtures, network labs, virtual machines, and documentation.

How it works

A MAC address is 48 bits, shown as six bytes. The tool draws six random bytes from the browser’s secure random generator, then adjusts the first octet’s two low-order bits so the result is a proper, safe address: it sets the locally-administered bit (so the address is marked as locally assigned, not allocated to a hardware vendor via an OUI) and clears the multicast bit (so it is unicast). This guarantees the address is a valid, locally-administered unicast MAC that cannot collide with real vendor-assigned hardware.

The remaining bits are fully random. The bytes are then formatted with your chosen separator and letter case.

Example

A generated address in colon, lowercase format might be:

a2:3f:9c:14:7b:e0

The same address in other formats:

Note the first octet a2 has the locally-administered bit set and the multicast bit clear. Generation happens entirely in your browser; nothing is sent anywhere.