AirTag Even Knows When You're On The Wrong Floor | Screen Rant
When Apple announced its location beacon, the AirTag, it described Precision Finding as having great accuracy but didn't actually detail how accurate it was and what would happen if a lost item was above or below the owner. However, as the device has made its way into the hands of users, some additional information has come to light. For example, the Find My app can sometimes identify when an AirTag is on another floor, or 'a different level' to use Apple's phrasing.
The AirTag's Precision Finding mode is only available when using an iPhone 11 or iPhone 12, since those devices have Apple's U1 ultra-wideband chip results in higher accuracy. Owners of an older iPhone or an iPhone SE can also locate an AirTag, but since those devices rely on Bluetooth for connecting to the beacon, the function is similar to that of a Tile tracker, meaning the general vicinity of the AirTag (and lost item it's attached to) can be found on a map, but close range directions are not available. Instead, a sound can be triggered on the missing AirTag.
For those that own an iPhone 11 or iPhone 12, the AirTag accuracy is quite satisfying, going so far as to let the searcher know if an AirTag is on a different floor. Within seconds of opening the Find My app, and selecting the item tab, all of the AirTag beacons paired to the iPhone are listed, showing their approximate location on a map view. The list appears at the bottom and tapping a particular item brings up the controls to find, play a sound or mark the AirTag as lost. If an AirTag is suspected to be nearby, playing a sound might make it easy to locate, but it's much more fun to select the find option.
When using a recent flagship iPhone, Precision Finding will be available and the Find My app will instruct the user to move around a bit to help locate the missing AirTag. It takes a few seconds and if the item is not where expected, a bit of walking could be required. When within range, which may vary, the Find My app will display the distance and show an arrow that points in the direction of the lost item. The units can be set to feet or meters and the distance is shown with an accuracy of one decimal place. This means setting the measurement to feet will offer the most precision, since one-tenth of a foot is much shorter than one-tenth of a meter.
Searching for an AirTag with Precision Finding shows an arrow that provides a two-dimensional heading, but doesn't give any indication of the height or vertical position of the missing item. However, Apple built in a notification to alert the user when an AirTag is located several feet above the iPhone used for searching. This can help greatly when narrowing in on a missing item, one floor above or below. Unfortunately, for items lost in a multi-story building, there is nothing to indicate whether the AirTag is higher or lower, though raising and lowering the iPhone will reveal which direction to travel on the stairs or elevator. It's unlikely the ultra-wideband signal would penetrate through multiple floors, so losing an item in a high-rise could require a search on every other floor. Most likely, the floor that was visited would be known, however, so this is unlikely to affect most AirTag users.
Source: Apple