MAC Address / OUI Lookup
Identify the vendor of any MAC address using the complete IEEE OUI registry — all 39,000+ prefixes bundled client-side. No API calls, no rate limits, works offline after first load.
How to Use
- Paste a MAC address (44:38:39:AB:CD:EF, 44-38-39-AB-CD-EF, 443839ABCDEF — all work).
- The vendor name appears instantly; no network call needed.
- Also detects locally-administered ("random"/"private") MACs used by Apple / Android privacy features.
Paste any MAC above and hit Look up — vendor + block info lands here instantly, fully offline.
Details detected
Frequently Asked Questions
How accurate is this?
It uses the complete IEEE MA-L (Organisational Unique Identifier) registry — the authoritative source. Vendors can change the registry; the data is re-pulled any time tools/_dev/build-oui-db.py is re-run.
What is a random MAC?
Devices assign themselves a "locally-administered" MAC to avoid being tracked across Wi-Fi networks. The second-lowest bit of the first byte is 1 in those MACs — the tool flags them.
Is this really offline?
First load fetches the 1.3 MB OUI JSON once. After that it's cached by the browser and works without a network call. No external service involved.
Common Use Cases
Identify a device
Saw an unknown MAC on your network? Find out who made the device.
Inventory audit
Cross-check MACs from ARP / DHCP dumps against the vendor list.
Spot spoofing
A random-looking MAC that doesn't match any known vendor is often spoofed.
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