How to use the MAC address validator
Choose Single Address to check one candidate or Bulk Addresses to check a list. The tool validates the supplied text and reports status, canonical values where available, bit flags, duplicates, and errors.
Validate one MAC address
- Enter an address in the single-address input.
- Results update automatically as you type.
- Read the result. A valid address shows its canonical colon-separated value, detected format, byte length, and bit flags.
Valid input has 12 hexadecimal digits for EUI-48 or 16 for EUI-64. The accepted notations are colon-separated, hyphen-separated, Cisco dot notation, and compact notation without separators.
Validate a list of MAC addresses
- Open Bulk Addresses.
- Paste entries one per line or separate them with commas.
- Results update automatically as you paste or type.
The results table shows status, flags, duplicate row references, and errors. For a valid row, the Address cell shows the canonical value. If no canonical value is available, it shows the original value. Duplicate entries remain in the results and are marked rather than removed.
Understand validation results
The validator checks the hexadecimal digit count and separator notation. It accepts 12-digit EUI-48 and 16-digit EUI-64 values. For valid addresses, it reads two flags from the first octet:
- The I/G bit identifies the address as unicast or multicast.
- The U/L bit identifies it as locally or universally administered.
In bulk mode, entries with the same hexadecimal value are flagged as duplicates of the earlier row, even if their separators differ.
Fix invalid input and separator errors
The tool reports non-hexadecimal characters separately. For the length check, it removes separators and other non-hexadecimal characters, then counts the remaining hexadecimal digits. The error reports that count when it is not 12 or 16.
Complete colon, hyphen, dot, and compact patterns are recognized. Mixed or unrecognized separator groupings can produce Separators don't match a recognized colon, hyphen, or dot grouping. Correct the grouping and run the validation again.
Copy or download bulk results
After validating a list, select Copy CSV to place the results on the clipboard or Download CSV to save them as mac-address-validation-results.csv. The CSV includes original and canonical values, validity, format, byte length, flags, duplicate row references, and errors.
Scope and limitations
Validation runs locally against the text you supply. The tool checks syntax and encoded bit flags only. It does not perform a vendor/OUI lookup, identify a device or owner, discover devices, ping, or query a network.
Frequently Asked Questions (FAQs)
Does this tool tell me what device or vendor a MAC address belongs to?
No. It checks syntax and reports the unicast/multicast and locally-administered bit flags encoded in the address itself. It performs no OUI/vendor lookup.
Does this tool scan my network?
No. Validation runs locally in your browser against the text you supply. The tool does not discover, ping, or query any device, and it performs no network scan.
What separator formats are supported?
Colon, hyphen, dot (Cisco), and compact notation are supported. A valid single result shows a canonical colon-separated value. In bulk mode, valid rows show the canonical value; rows without one show the original value.
What are the unicast/multicast and locally-administered flags?
Both are read from the first octet's low bits: the I/G bit distinguishes unicast from multicast, and the U/L bit distinguishes locally administered from universally administered addresses.