Printable Protractor

Line up the flat baseline of the protractor with one side (ray) of the angle you're measuring, with the center point exactly on the angle's vertex. Read the degree value where the second ray crosses the curved edge.

• Print at 100% scale — a scaled protractor will read every angle incorrectly.
• For angles greater than 180°, measure the remaining reflex angle and subtract from 360°.
• Glue or tape the print to thin cardboard for a sturdier, reusable protractor.

Need straight-edge measurements too? Build one with the custom ruler builder, or try the millimeter ruler.

• Verify your printer first. Run the credit-card accuracy test before trusting a single angle reading — a "Fit to page" print will read every angle wrong, even though the protractor still looks correct at a glance.
• Mount it for repeat use. Glue or tape the printed sheet to thin cardboard or a cereal-box panel, then trim along the outer arc with scissors or a craft knife for a rigid, reusable protractor.
• Punch the vertex for pinpoint accuracy. A small pinhole at the center dot lets you mark the exact vertex through the paper before lining up the baseline — more precise than eyeballing it.
• Extend the baseline for long rays. If the angle's sides are longer than the protractor, lay a ruler along the baseline edge first, then slide the protractor to the vertex — the ruler keeps the reference line straight.
• Reading past 180°? This protractor covers a half-circle. For reflex angles, measure the smaller angle on the other side and subtract it from 360°.
• Keep it flat when storing. Paper and even cardboard-backed protractors can warp over time — store it flat inside a book or folder rather than rolled up, so the arc stays true next time you need it.