# How do I use my iPhone as a level?

Open the Measure app, tap Level, and hold the iPhone against what you want to check. Apple says those measurements are approximate. Level Tool is a separate clinometer for the same kind of rough check, and neither one replaces a real level for structural or safety-critical work.

By Aivana LLC. Updated 3 November 2026.

## What to do

The phone you already own has a level. A dedicated app is for when you want that reading in a tool built only for angles. The limit is the same either way: the sensors are approximate.

1. **Use the built-in level first if you only need level.** Apple's guide: open Measure (it lives in Utilities), tap Level, and hold an edge of the iPhone against the object, such as a picture frame. Rotate until you see 0 degrees and the display turns green.
2. **Read it as approximate.** Apple says the level shows whether something is level, or how many degrees it is off, and that the measurements are approximate. A case, a soft surface, or a shaky hand moves the number.
3. **Zero it if you are comparing two slopes.** In Measure, tap the screen to capture the first slope, then hold the phone on the second object until it matches. Tap again to reset. In Level Tool, use the zero or calibrate control while the phone sits on a surface you already trust with a bubble level.
4. **Check the phone against a known level.** Put a hardware bubble level on a shelf, then put the phone on that same shelf. If the app is far from zero, zero it and check again. If it still wanders while the phone is still, do not trust it for that job.

## What not to do

- Do not hang a staircase, set a foundation, or sign off a roof pitch from a phone.
- Do not leave a thick case on and expect the back of the case to be the same angle as the phone.
- Do not assume two phones will match each other to a tenth of a degree. Accuracy varies by device.

For anything that could fall on someone, hold weight, or has to meet a code, use the instrument that job requires and someone qualified to use it.

## Where Level Tool helps

Level Tool is the dedicated clinometer: a level reading and an angle, including a zero you set, without the measuring-tape part of Measure. It is still the phone's sensors. It is a check, not a certification.

## Other ways

### The Measure app

Already on the iPhone. Best when you want level or a quick slope and you do not need a separate tool.

### A bubble level or a digital inclinometer

Use this when the result matters. They are built for the job. The phone is for a frame, a shelf, or a rough look.

## Questions

### How accurate is a phone level?

Approximate, and it varies by iPhone and by how steadily you hold it. Apple uses that word for the built-in level. Do not treat a phone as a calibrated instrument.

### The number will not sit still.

Hold the phone firmly against the surface. Sensors pick up small movement. If it jumps while the phone is resting on a solid shelf, zero it on a known level and try again.

### Can I measure a vertical frame?

Yes. Hold an edge of the phone against the frame, as Apple describes for the Measure level. Green and zero means that edge is level, approximately.

### Does it need the internet?

No. The sensors are in the phone.

## Sources

- Apple Support: Use iPhone as a level. https://support.apple.com/guide/iphone/use-the-level-iphbd435673d/ios

## Related guides

- [How do I level an RV or camper with my phone?](https://aivanaapps.com/apps/level-tool/guides/level-rv-with-phone/)

App: https://aivanaapps.com/apps/level-tool/
App Store: https://apps.apple.com/app/id6828946545