Quick example
Convert 00:1A:2B:3C:4D:5E between MAC formats
The address 00:1A:2B:3C:4D:5E can also be written as 00-1A-2B-3C-4D-5E, 001A.2B3C.4D5E, or 001A2B3C4D5E. The separators and letter case change, but the same six bytes remain.
Format reference
Common ways to write a 48-bit MAC address
| Format | Example | Grouping |
|---|---|---|
| Colon-separated | 00:1A:2B:3C:4D:5E | Six groups of two |
| Hyphen-separated | 00-1A-2B-3C-4D-5E | Six groups of two |
| Cisco dotted | 001A.2B3C.4D5E | Three groups of four |
| Plain hexadecimal | 001A2B3C4D5E | No separators |
Reading the bits
What the MAC address analysis means
Individual or group bit
The least significant bit of the first byte is zero for an individual unicast address and one for a group multicast address. All six bytes set to FF form the broadcast address.
Universal or local bit
The next bit is zero for a universally administered address and one for a locally administered address, including many privacy-randomized addresses.
OUI and device portions
For universally administered addresses, the first 24 bits can be an assigned organizational prefix. The final 24 bits are the device-specific portion.
Modified EUI-64
This derived 64-bit identifier inserts FFFE between the two MAC halves and flips the universal/local bit. It is an interface identifier, not a complete IPv6 address.
Vendor identification
Why this tool shows the prefix but not a manufacturer
Vendor names require a current external OUI registry, while locally administered or randomized MAC addresses may not identify a manufacturer at all. To keep the formatter private, fast, and dependency-free, it shows the first 24 bits without sending the address to a lookup service.
Common questions
MAC address formatter FAQ
What MAC address formats can I convert?
Enter six colon-separated or hyphen-separated bytes, three Cisco dotted groups, or 12 plain hexadecimal digits.
Can a MAC address identify the manufacturer?
The first 24 bits of a universally administered address may be an assigned OUI. A current registry is needed to map it, and local or randomized addresses are not reliable manufacturer identifiers.
What makes a MAC address unicast or multicast?
The least significant bit of the first byte is zero for individual unicast and one for group multicast. FF:FF:FF:FF:FF:FF is the broadcast address.
Does this tool send the MAC address anywhere?
No. Formatting and analysis run entirely in your browser without a network or vendor-database lookup.