ToolwebHow to use this tool
- Enter colon-separated, hyphenated, Cisco dotted or unseparated hexadecimal text.
- Read the normalized address and its group/administration bit flags.
- Copy the format your equipment expects; distinguish derived IPv6 forms from actual device addresses.
Derive an identifier from a local MAC
- Input and settings
- 02:1A:2B:3C:4D:5E
- Result
- 02:1a:2b:3c:4d:5e; locally administered; EUI-64 001a:2bff:fe3c:4d5e
The value is calculated by flipping the U/L bit and inserting FFFE, not read from a device.
Different separators, identical bits
Colon and hyphen formats use six groups of two digits; Cisco dotted form uses three groups of four. Twelve unseparated hexadecimal digits are also accepted. Invalid characters and incomplete octets are rejected rather than stripped until the input happens to look valid.
The low bit of the first octet distinguishes individual and group addressing; the next bit indicates local administration. These flags do not identify the manufacturer, device class or authorization to use the address.
Derived EUI-64 is only one construction
Modified EUI-64 inserts FFFE into the 48-bit identifier and inverts the U/L bit. A computed link-local form under fe80::/64 is also shown, but an operating system may actually use a different stable or temporary interface identifier.
The page does not read your network interfaces or query a manufacturer database. It does not change addresses, perform spoofing or connect to equipment, and a native 64-bit MAC identifier is outside the input format supported here.
Common questions
Why is no manufacturer name shown?
No external OUI database is queried, and the address flags alone cannot establish a manufacturer.
Why does the derived link-local address differ from my device?
Your operating system may use a privacy-preserving or stable identifier scheme rather than a MAC-derived EUI-64 identifier.