MAC Address Formatter
Convert a MAC address between colon, hyphen, Cisco dot and bare formats, see whether it is unicast or multicast and locally or universally administered, or generate one.
Free · No sign-up · Your inputs stay in your browser
Input
Format and inspect a MAC address
Output
00:1a:2b:3c:4d:5e
| Colon (Linux, macOS) | 00:1a:2b:3c:4d:5e |
|---|---|
| Hyphen (Windows) | 00-1A-2B-3C-4D-5E |
| Dot (Cisco) | 001a.2b3c.4d5e |
| Bare | 001a2b3c4d5e |
| Upper case | 00:1A:2B:3C:4D:5E |
| Cast | unicast |
|---|---|
| Administration | universally administered (burned in by the vendor) |
| OUI (vendor prefix) | 00:1A:2B |
| Broadcast | no |
The two lowest bits of the first byte carry meaning: bit 0 marks a multicast address and bit 1 a locally administered one. A generated MAC sets bit 1 and clears bit 0, so it can never collide with a vendor's address. The vendor behind an OUI is listed in the IEEE registry.
Runs in this browser. Nothing you paste is sent to a server.
About this tool
Method, assumptions, practical next steps, and limits.
The two bits that matter
Bit 0 of the first byte marks a group (multicast) address, and bit 1 marks a locally administered one. Virtual machines, containers and phones that randomise their Wi-Fi address set bit 1, so a MAC whose second hex digit is 2, 6, A or E is almost certainly not a hardware address. The first three bytes of a universal address are the vendor's OUI, listed in the IEEE registry.
Randomised addresses
iOS, Android and Windows use a different random MAC per Wi-Fi network by default, so DHCP reservations and MAC-based allow lists see a new device after a reset. For a fixed address on a VM or a test, generate a locally administered one so it cannot collide with real hardware.