The built-in digital compass works like a magnetic-needle compass. The accuracy of digital compass headings can be affected by magnetic or other environmental interference, including interference caused by proximity to the magnets contained in the phone earbuds. The compass may need to be calibrated from time to time.

You can calibrate the compass by opening up the app, and moving the phone in a certain manner. Here are two types of movements to try:

Three axis rotations

1. Put the phone on a flat surface with the display pointing up.
2. Move the phone slowly, 5 seconds per full rotation is OK.
3. Rotate the phone three full cycles around the axis pointing upward.
4. Rotate the phone three full cycles around the axis pointing away from you.
5. Rotate the phone three full cycles around the axis pointing right.

The “figure 8 pattern”