What is a protractor?

  Shop for Protractor Sets     
  Blue, semi-circle, protractor, 180 degree  

A protractor is an instrument used to measure angles. 

  Mathematical formula, pen, maths lessons, protractors  

You may well have used them in your mathematics lessons.

  "360 degrees" with a blue arrow looping around in a clockwise direction; angles, 360 degrees, protractors;  

Angles are measured in degrees. There are 360 degrees in a full circle.

  Plastic, semi-circle, protractor, angles  

Many protractors are a semi-circular shape made from plastic…

  Several 180 degree angles; angles, 180 degrees, protractors  

…and can measure up to 180 degrees.

  360 degrees, protractor, angles  

However, it is possible to buy protractors which measure up to a full 360 degrees.


In construction, protractors can be found as a part of several tools, including:

  A red Faithfull combination square set; rule, ruler, blade, square head, centre head, protractor head  
  • Combination square sets

  A Mitutoyo bevel protractor; angles, protractor  
  • Bevel protractors

  A protractor and depth gauge; angles, protractor  
  • Protractors and depth gauges

   digital angle gauge with an On/Off button and a "Zero" button; angles, liquid crystal display, magnets  
  • Digital protractors (and angle gauges)