Questions
How accurate is a phone level?
After calibration most phones read within a few tenths of a degree. A case or a camera bump that rocks the phone adds error, so calibrate the phone the way you will use it.
How do I calibrate the level?
Put the phone on a surface you know is level, wait for the reading to settle and press Calibrate. That position becomes zero until you clear it.
What is the difference between degrees and percent slope?
Percent slope is the rise per 100 units of run. A 1 degree tilt is about 1.75 percent, and 45 degrees is 100 percent.
Why does nothing move on my computer?
Computers have no tilt sensor. Open this page on a phone or tablet.