PrintReadyKit

Tool

Printable protractor

A protractor you can print and cut out: the classic 180° half circle with two scales, or a full 360° circle with maths or compass numbering, marked every degree, at any size that fits A4 or Letter. The page carries a check square that shows whether it printed true.

Shape
Units
Sizes

Up to 188 mm across on A4. At 150 mm, one degree is 1.3 mm of edge.

Paper
  • Print the PDF at Actual size or 100%.
  • Card stock holds its shape; transparency film lets you see the drawing through it.
  • Cut along the solid outer line and pierce the centre point.
180 degree protractor, 150 mm acrossPrint on A4 at Actual size / 100%. Cut along the solid outer line; pierce the centre point to line it up.18001701016020150301404013050120601107010080909080100701106012050130401403015020160101700180Check square: 50 mm on each side.Measure both sides with a ruler.Equal sides: the page kept its shape, so angles read trueeven if it printed a little large or small.50 mm exactly: the page also printed at 100%.Unequal sides: the printer stretched the page. Print againat Actual size, with scaling and borderless printing off.printreadykit.com/tools/printable-protractor

How to measure an angle

  1. Put the centre point exactly on the corner of the angle.
  2. Turn the protractor until the 0–180 line lies along one arm.
  3. Read where the other arm crosses the edge, on the scale that counts up from 0 on the first arm.

To draw an angle, do the same in reverse: mark the centre and the 0 line, make a dot at the angle on the edge, and join the dot to the centre with a ruler — the printable ruler prints one to match.

Why a square, not just a ruler line

A protractor shrunk evenly still reads every angle correctly; only a page stretched more one way than the other bends its angles. So the check is whether the square’s two sides match. If you also need the stated size — to lay out a template, say — measure them against 50 mm, or run the print scale calibration test to find the exact percentage your printer prints at.

Keeps these settings in the link. Useful for moving from a phone to the computer with the printer on it.

Frequently asked questions

How do I measure an angle with a printed protractor?

Put the centre point on the corner of the angle and lay the 0–180 line along one of its arms. Read where the other arm crosses the edge: use the scale that starts from 0 on the first arm — the inner scale when that arm points right, the outer scale when it points left. If the arms are short, extend them with a ruler first so they reach the edge.

Will it be accurate if my printer scales the page?

For angles, yes — as long as the printer scales both directions equally. Shrinking a page to 97% shrinks the protractor but leaves every angle on it unchanged. What would spoil it is a page stretched more one way than the other, which is rare but happens with some drivers. The square on the page tells you: if its two sides measure the same, the angles are true. If they also measure exactly 50 mm (or 2 in), the protractor is at its stated size too.

What is the best paper to print a protractor on?

Card stock (160–250 gsm) keeps its shape when you cut it out and holds a pencil line along the edge. For a protractor you can see through, print on transparency film made for your kind of printer — inkjet film for an inkjet, laser film for a laser — so the drawing underneath shows through and you can line up the arms directly.

What is the difference between the 180° and the 360° protractor?

The half circle is the classroom protractor, with two scales so that any angle up to 180° can be read from either side. The full circle measures reflex angles past 180° in one reading, and with compass numbering — 0 at the top, counting clockwise — it reads bearings on a map.

How big a protractor can I print?

Up to 188 mm across on A4 and 193 mm on US Letter for the half circle, and 183 mm and 165 mm for the full circle, which also has to leave room for the check square on the same sheet. Bigger protractors read more precisely: on a 180 mm protractor one degree is 1.6 mm of edge.

Measuring and scale tools

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