Angle measurement tools

A precise on-screen protractor. Drag a vertex and two arms for an exact reading, or use the classic rotating protractor face with both scales. Paste a screenshot to measure anything on your screen.

Drop, paste or upload a photo and measure any angle in it. Magnifier for precise placement, perspective correction for off-angle shots, unlimited measurements, and export to PNG, CSV or JSON.

A digital level, inclinometer and plumb gauge using your phone's tilt sensor. Two-position calibration, auto-hold when steady, and readings in degrees, percent grade, roof pitch or rise-and-run.

Aim your camera at a roofline, a tree or a slope and read the angle of elevation. Add the distance to work out the height, and hold the reading to note it down.

Track how far a joint moves. Rest your phone on the moving limb to measure a range of motion, or enter a reading from a physical goniometer, then compare left and right in a log that stays on your device.

Set up a half or full-circle protractor, size it for A4 or Letter paper, add a marked angle to use as a cutting template, and print it at exactly the right scale, with a check bar to confirm.

Convert a roof pitch between x:12, degrees and percent, and get rafter and hip factors, cut angles, rafter length and roof area — with the minimum pitch for each roof covering from the International Residential Code.

Enter any two of rise, run, sloped length and angle to solve the rest. See the slope as degrees, percent grade, a 1:N ratio, a pitch and per mille.

Enter the height to climb and get the ramp length, the number of runs and landings, and whether handrails are needed — checked against the 2010 ADA Standards.

Convert an angle between degrees, degrees-minutes-seconds, radians, gradians, turns, arcminutes, arcseconds, mils and milliradians, with its slope, related angles and trig values.

Get the miter and bevel saw settings for picture frames and trim, crown molding on any wall corner, and boxes or planters with sloping sides — including corners that are not 90°.

Enter the floor-to-floor height to get the number of risers and treads, riser height, total run, stair angle and stringer length — checked against the International Residential Code and the comfort rule.

Enter any three sides and angles to solve the rest — including the ambiguous case where two different triangles fit — with area, perimeter, heights and the inscribed and circumscribed circles.

Find the interior, exterior and central angles of any regular polygon, work out how many sides an angle implies, or find the missing angle of any polygon — with area and radii from a side length.

Find the complement, supplement and explement of an angle, or check whether two angles are complementary, supplementary or explementary.

Types of angles

Acute, right, obtuse, straight, reflex and full angles, the angle pairs you meet in geometry, and angles of elevation and depression.

Degree angles

See any angle drawn to scale, with a chart of common angles and practical ways to make, check and cut 15°, 30°, 45°, 60° and 90°.

Incline bench angle

What 15°, 30°, 45° and 60° do, what the research found, and how to find the angle your bench is really at with your phone.