Yuzool

Protractor online

Drag the two arms over any angle to read it in degrees.

60.0°Reflex 300.0°

Drag the two round handles to the arms of your angle, and the centre dot to its corner. Lay a small object on the screen, or line the arms up with a photo. Arrow keys nudge the selected arm.

About the online protractor

This protractor has two arms you drag freely around a centre point, so it can measure any angle from 0° to 360°: it shows the angle between the arms and the reflex angle on the other side. Snap to 1° keeps the reading to whole degrees, or switch it off for tenths.

It needs no sensors, so it works the same on a phone, a tablet and a computer.

How to use it

  1. Drag the centre dot to the corner (vertex) of the angle.
  2. Drag each round handle along one of the lines.
  3. Read the angle in the panel, and the reflex angle under it.
  4. Lay a small object on the screen, or line the arms up with a photo or a drawing. Reset puts the arms back.

Good for

  • Checking angles in maths homework and geometry drawings
  • Measuring the angle of a corner on a small part or a tile
  • Reading an angle from a photo, such as a roof line or a ramp
  • Checking a knife or chisel bevel held up to the screen

Questions

How do I measure an angle with the online protractor?

Put the centre dot on the corner of the angle and drag the two handles along its lines. The angle between them is shown in degrees.

What is a reflex angle?

The angle on the outside, between 180° and 360°. The two always add up to 360°, so a 60° angle has a reflex angle of 300°.

Do I need to calibrate the protractor?

No. Angles don't depend on the screen size, so it is accurate on any screen without calibration.

More tools in Bubble Level

Everything is in one free app: Bubble Level. Guide: How to hang a picture straight.