Free to try, on iPhone and Android.
Free to try on the App Store and Google Play. No physical protractor, ad-free, works offline.
Why choose Protractor?
- Free to try
Download free and start with a free trial. After that, a subscription unlocks the full feature set — and there are never any ads.
- No physical tools
Uses the motion sensors and camera already in your phone. No protractor, level, or inclinometer to buy.
- Works offline
All measuring is on-device. No account, no internet, no tracking.
- Many modes in one
Angle, slope, incline, roof pitch, camera protractor, and bubble level — all in a single app.
Device compatibility
Protractor runs on iPhone 8 and newer, and on Android 8.0 and newer. Every modern phone ships with the accelerometer and gyroscope the app needs, and the camera protractor works on any model with a rear camera. Sensor-based readings are accurate to within about a degree for everyday DIY, woodworking, and home tasks.
On Android? The protractor app for Android page covers what your phone needs and how the sensors differ from iPhone.
Questions before you install? See the FAQ or read how the app works in How it works.
Measure any angle,
right from your pocket.
Protractor turns your phone into a precision angle finder, level and inclinometer. Measure anything, anywhere.
Download the App