How to Turn On the Level Tool on an iPhone

If you are trying to hang a picture frame perfectly straight, or install a new shelf in your living room, you do not need to rummage through your garage for a physical spirit level. Your iPhone contains highly sensitive, military-grade accelerometers and gyroscopes that can instantly detect exactly how the phone is tilted in 3D space.

Apple harnesses these internal sensors to power a built-in digital Level tool, allowing you to use the physical edge of your phone to ensure surfaces are perfectly horizontal or vertical.

How to Access the Level Tool

In older versions of iOS, the Level was awkwardly hidden inside the Compass app. Apple has since moved it to a much more logical location: the Measure app.

1. Locate and open the Measure app on your iPhone. (It has a black icon with a yellow ruler. If you cannot find it, swipe down on your home screen and type “Measure” into the search bar).
2. Look at the very bottom of the screen. You will see two tabs: “Measure” and “Level”.
3. Tap on Level.

How to Use the Level

The digital level functions in two completely different ways depending on how you hold your phone.

1. The Edge Level (For Walls and Pictures)

If you want to check if a picture frame is hanging straight, you need to use the edge of your phone.

1. Hold your iPhone vertically (portrait mode) or horizontally (landscape mode).
2. Rest the physical side-edge of the iPhone directly on top of the picture frame or the shelf.
3. The screen will display a large white circle cut in half by a horizon line, along with a number representing degrees.
4. Slowly tilt the phone left or right. As you approach a perfectly flat 0°, the screen will instantly turn bright green to confirm the surface is perfectly level.

2. The Surface Level (For Tables and Floors)

If you want to check if a dining table or a floor is perfectly flat, you need to use the back of your phone.

1. Place your iPhone completely flat on its back directly on the table surface.
2. The screen will change to display two white circles (a small one inside a larger one).
3. As you tilt the table, the small circle will roll around like a marble. Your goal is to get the small circle perfectly centred inside the large circle.
4. When the table is perfectly flat (0°), the screen will instantly flash bright green.