MAC Address Validator
Paste a MAC address in any common format — colon, dash, dot (Cisco) or plain — and get validation for 48 bit and 64 bit EUI-64 addresses, normalized output, the unicast/multicast and U/L admin bits, and the vendor OUI prefix.
Normalized formats
Address analysis
Byte breakdown
| Byte | Hex | Decimal | Binary | Role |
|---|
No vendor database is bundled, so only the OUI prefix (first 3 bytes) is shown. The bits are read from the first byte of the address.
How to use
- Paste or type a MAC address — separators are optional and mixed styles like 00-1a.2B3c:4D5E also work.
- Press Validate MAC Address to see the normalized formats, the unicast/multicast and U/L bits, and the byte table.
- Use the sample buttons to see a 48 bit and a 64 bit EUI-64 address analyzed.
Tips
- A 48 bit address has 12 hex digits (6 bytes); an EUI-64 address has 16 hex digits (8 bytes).
- The Cisco dot format groups 48 bit addresses as AABB.CCDD.EEFF and EUI-64 addresses as AABB.CCDD.EEFF.GGHH.
- Broadcast and multicast addresses start with 01, 33, or FF in the first byte.
Frequently Asked Questions (FAQ)
What does this MAC address validator do?
It checks whether a MAC address is a valid 48 bit or 64 bit EUI-64 address, accepts colon, dash, dot and plain input formats, normalizes the address to standard formats, and shows the unicast or multicast and universally or locally administered bits.
Which MAC address formats are accepted?
Colon separated (AA:BB:CC:DD:EE:FF), dash separated (AA-BB-CC-DD-EE-FF), Cisco dot format (AABB.CCDD.EEFF), and plain hex with no separators. EUI-64 addresses can use the same styles with 8 groups.
What do the U/L and I/G bits mean?
The I/G bit (least significant bit of the first byte) tells whether the address is unicast or multicast. The U/L bit (second least significant bit) tells whether the address is universally administered by the manufacturer or locally administered.
Is the MAC address validator free?
Yes, the MAC address validator is completely free to use with no signup. Everything runs in your browser.