What it means
MAC randomisation is a privacy feature that makes a device change the identifier it broadcasts on a schedule, so it cannot be tracked across locations by a stranger.
Your iPhone does this. So do AirTags, modern trackers and most current consumer hardware. It is the reason a scan often shows devices with no readable name and a string that changes.
This creates an obvious tension. The same feature that protects you from being followed also makes it harder to confirm that the anonymous device in your scan today is the same one you saw yesterday.
The practical workaround is not to chase identifiers. Compare locations instead: scan at home, scan somewhere far away, and look at what persists across both.
Related terms
The other pieces of Bluetooth vocabulary that change how you search.
- UWB: Ultra-wideband
- Bluetooth Classic: The older streaming mode
- Transmit power: How loudly a device broadcasts
- Coin cell: The battery in most tags
- Beacon: A device that only broadcasts
- Bluetooth scanner for iPhone, Scan tab
- How to find something in a hotel room before you check out, Method
- Full glossary, the complete list
Common questions
Why do some Bluetooth devices have no name?
Because they rotate their identifiers for privacy. An anonymous device is not suspicious by default, your own phone looks the same to everyone else.
Can I still detect a tracker that randomises its address?
You can detect that something is broadcasting. Confirming it is the same device over time is harder, which is why the two-location comparison matters more than the identifier.
In the app: The scan shows this value live for every device around you. Read about Bluetooth Scanner.