Multi Bubble Level

Displays precise angle between two or more devices, making it possible to perfectly align physical objects in relation to one another.

Measuring relative level comes in handy for aligning items that have significant distance or physical obstruction between them. Sometimes there’s a need to determine angle between separate objects, rather than to see how flat they lay relative to the planet’s surface.

With only one device running the app, Multi Level works as a conventional (single) bubble level.

While open, the app uses Bluetooth to broadcast its magnetometer’s data (roll, pitch, and yaw). At the same time, it listens to other devices running this app, comparing own physical orientation to theirs. This allows communication without actually having to pair any of the devices — there’s no need to tap on anything, deal with PIN codes, etc. Everything happens automatically once the app is launched.

You don’t need to purchase this app more than once, as long as all devices use the same Apple ID. Any old or new iPhone/iPad/iPod that supports iOS 15.0+ should suffice.