If you are trying to hang a picture frame perfectly straight, or attempting to level a wobbly desk, you do not need to hunt through your garage for a physical spirit level. Apple cleverly repurposed the internal gyroscope and accelerometer sensors inside every iPhone to create a highly accurate, digital leveling tool.
This feature is not located in the Settings app; it is actually a dedicated secondary mode hidden inside the native Measure application.
How to Use the Level Tool
- Locate and open the default Measure app on your iPhone. (It has a black icon with a yellow ruler). If you deleted it, you can reinstall it for free from the App Store.
- At the very bottom of the screen, tap the tab labeled Level.
The interface will instantly change to a minimalist black screen featuring two white circles. You can use this tool in two distinct ways, depending on how you hold your phone.
Vertical Leveling (Hanging Pictures)
To check if a picture frame or a vertical wall is perfectly straight:
- Hold your iPhone upright (in portrait or landscape orientation).
- Rest the physical edge of your iPhone directly against the top or side of the picture frame.
- The screen will display a single white line and a degree measurement.
- Slowly tilt your phone (and the frame) until the number reads precisely 0°.
- When perfect level is achieved, the entire screen will instantly turn bright green.
Horizontal Leveling (Desks and Tables)
To check if a flat surface, like a table or a shelf, is perfectly even:
- Place your iPhone completely flat on its back directly on the surface.
- The interface will change from a line to two overlapping circles.
- The number in the center displays how many degrees the surface is tilted.
- Adjust the legs of your table until the two circles perfectly overlap in the dead center of the screen.
- When the surface is perfectly flat (0°), the screen will turn bright green.