Protractor: Angle Measure

Digital protractor readings help you compare slopes, check tilt and explore angle calculations with your phone. Protractor: Angle Measure combines a sensor-based angle finder, a two-axis level and tools for polygon and cutting calculations. Use it for study, craft planning and everyday checks where an approximate reading is appropriate. READ THE PHONE'S TILT The angle meter uses the accelerometer's gravity readings to calculate pitch, roll and an angle relative to your zero reference. It does not measure a full 360-degree physical rotation. Keep the phone steady against a suitable surface and allow the reading to settle. Case edges, movement and sensor behaviour can affect the result; the number of displayed decimals is not an accuracy guarantee. ZERO, HOLD AND RECORD Set the current position as a zero reference when comparing two slopes. Keep a held reference value alongside the live reading. Start a recording session to track elapsed time, minimum, maximum and average angle with a chart, then stop or reset the session. Recording here means a sequence of angle readings, not audio or video. ANGLE UNITS AND SLOPE Switch the angle display between degrees, radians and NATO mils. View slope as a percentage and as rise per 12 units of run. These are different representations of the angle, not measurements of a board's length. Near vertical, some slope representations become unbounded and can display an infinity symbol. TWO-AXIS LEVEL The level view shows pitch and roll together and provides a near-level indicator. Set a reference calibration or clear it when changing surfaces. Use the display to compare small tilts on a tabletop or a project surface, then confirm any important alignment with a suitable physical instrument. Phone sensors and the surface used for calibration limit the result. POLYGON ANGLES Tap points on the screen to make a polygon and close the shape to calculate its interior angles. Compare their total with the expected total for a simple polygon and share the values as text. This is geometry from the points you draw; it is not a camera scan or a survey of a real room. Completed polygon corner values can be used by the compound-cut calculator. PLAN CUTS AND JOINTS Build cut lists with names, entered lengths in millimetres or inches, angles and angle adjustments. Review the angle total and share a list as text. Simple miter and compound miter/bevel calculations use your entered corner and slope values; presets help explore crown moulding and polygonal planter examples. Verify the setup against your equipment and project before making a cut. Entered lengths are not measured by the app. Up to five cut lists can be saved. SAVE A READING FOR LATER Keep up to 100 angle readings with labels and timestamps. Rename labels, remove entries or clear the saved list, and share readings as text. A CSV report can be shared through rewarded-ad access. Saved measurements retain the captured value and do not automatically update when the phone moves. LIMITS AND CONNECTIVITY All readings are approximate and phone-sensor based where applicable. This app is not a certified measuring instrument and does not promise 0.1-degree accuracy or replace tools needed for safety-critical or precision work. The measurement and calculation tools use local sensor data and entered values. The app also contains AdMob advertising and Firebase Analytics, which use network services. Check your reference, placement and units before comparing results.

Lay the phone flat to read surface slope lengthwise, crosswise or diagonally; stand it on its bottom edge to read that edge’s angle. The label under the gauge identifies the mode. Tap through “Surface slope (fixed)”, “Edge angle (fixed)”, then Auto; fix Surface for steep surfaces. During recording, mode changes are disabled and min/avg/max keep one mode. Changing between surface and edge resets zero. The guide explains the modes.