What it means
Ultra-wideband is a separate radio technology that measures distance by timing how long a signal takes to travel, giving centimetre accuracy and a direction instead of a vague proximity.
This is what Apple’s Precision Finding uses on an AirTag with a compatible iPhone: an arrow and a distance in feet, rather than a signal bar.
It is genuinely better than Bluetooth for the final approach. It is also far more limited, because both devices need a UWB chip and most things you lose do not have one.
That is the trade-off in one line: UWB is more precise on a handful of devices, Bluetooth is less precise on almost everything.
Related terms
The other pieces of Bluetooth vocabulary that change how you search.
- Bluetooth Classic: The older streaming mode
- Transmit power: How loudly a device broadcasts
- Find My network: Apple’s crowd-sourced finding
- Attenuation: What blocks a Bluetooth signal
- RSSI: Received Signal Strength Indicator
- Bluetooth scanner for iPhone, Scan tab
- How to find something in the dark, Method
- Full glossary, the complete list
Common questions
Is UWB better than Bluetooth for finding things?
More precise, much less compatible. It works only where both devices have the chip, which excludes most headphones, speakers, wearables and budget tags.
Does my iPhone have UWB?
Recent iPhone models include a U1 or newer ultra-wideband chip. Older models do not, and neither does most third-party hardware.
In the app: The scan shows this value live for every device around you. Read about Bluetooth Scanner.