MAC Address Validator and Formatter
Validate and convert MAC addresses between common notations
About this tool
MAC Address Validator and Formatter checks one or many EUI-48 addresses and converts valid values between colon-separated, hyphen-separated, Cisco dot notation, plain hexadecimal, and uppercase formats. For each address it also reads the two low bits of the first octet to identify unicast versus multicast and universally versus locally administered addresses. Broadcast, all-zero, and invalid values receive clear labels. Everything is calculated locally without performing an OUI vendor lookup or sending addresses to a server.
Frequently Asked Questions
Which MAC address formats are accepted?
Colon, hyphen, Cisco dot, plain 12-digit hexadecimal, and whitespace-separated inputs are accepted.
What does locally administered mean?
It means the second-lowest bit of the first octet is set, so software or an administrator assigned the address instead of a globally registered OUI.
How is multicast detected?
A MAC is multicast when the least-significant bit of its first octet is 1.
Does the tool identify the hardware vendor?
No. Vendor lookup requires an OUI database; this tool focuses on syntax, normalization, and address bits.
Can I validate multiple MAC addresses?
Yes. Paste one address per line or separate values with commas.
Are MAC addresses sent anywhere?
No. Validation and formatting run entirely in your browser.
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