Online Protractor
No protractor at hand? Move the lines to read the angle, even on top of a photo.
—
Measure on a picture
Load a photo or drawing and the protractor sits on top of it. Nothing is uploaded.
Draw an angle
Draws the red line at the angle you enter, measured from the black line.
Images you load are only shown inside this page and are never sent anywhere.
How to use
- 1. Set the 0° lineDrag the black dot to turn the 0° line (black). Drag the black point in the middle to move the vertex.
- 2. Set the measuring lineDrag the red dot, or tap anywhere, and the red line points there. The angle appears in large type above.
- 3. Measure on a pictureUse “Choose an image” to load a photo or drawing, and the protractor sits on top. Put the vertex on the corner and line up the two lines with the edges.
FAQ
Who is this for?
Students and parents who need to check an angle without a protractor. Anyone measuring an angle in a photo or drawing, such as a roof pitch, a chair leg, posture or a line on a chart. Designers checking the angle of a line.
Can I hold an object against the screen?
Yes. Angles are correct at any size. To make the protractor real size (5 cm radius), calibrate your screen with a card on our ruler page, and that value is used here too.
Are my images uploaded?
No. Images you load are only displayed inside this page and are never sent anywhere. They disappear when you close the page.
What's the difference between 0–180° and 0–360°?
0–180° shows the smaller angle between the two lines, like a regular protractor. 0–360° shows the angle going counterclockwise from the black line to the red line, for reflex angles over 180°.
What are the supplementary and opposite angles?
The supplementary angle is 180° minus the angle. The opposite angle is 360° minus the angle, the angle on the other side of the lines.
Can I type an angle?
Enter a number under “Draw an angle” and the red line is drawn at that angle from the black line. Numbers over 180° switch to 0–360°.
Does it work on phones?
Yes. Drag the lines with your finger. On small screens, press “Full screen” to make it easier.
Is this online protractor tool free?
Yes, it is free with no sign-up. Images you load stay on your device and are never sent anywhere.
Premium
One Premium. Every upgrade, as much as you like.
- All paid features in every extension
- Premium features in Kitbench web tools
- Extensions we release later are included
- Up to 3 browsers per person (home, work, phone)
- Monthly¥980/month
- Yearly¥9,800/year (about ¥817/month)
- Lifetime¥14,800 once
More tools
BMI Calculator
BMI in US or metric units, your category, and the healthy weight range for your height.
Web tool · works in your browserCalorie Calculator
Daily calories to maintain or lose weight, using the official 2023 U.S. equations, with a formula comparison.
Web tool · works in your browserSleep Calculator
Bedtimes from your wake-up time, wake-up times if you sleep now, and nap times.
Web tool · works in your browserInternational Address Format
Pick a country and type the address – it comes out in that country's order, with an airmail envelope layout.
Web tool · works in your browserJapanese Address to English
Type a Japanese postal code and get the address in English, ready to copy field by field.
Web tool · works in your browserOnline Ruler (Actual Size)
An actual-size ruler you calibrate with a credit card. Measures in cm, mm and inches.
Web tool · works in your browser- NEW
Bingo Card Generator (Check Winners by Card Number)
Print number or word bingo cards in bulk. With a caller and winner check by card number.
Web tool · works in your browser - NEW
Random Team Generator (Balanced by Skill)
Split names into teams with even skill totals and spread tags. Keep apart, no repeat pairs.
Web tool · works in your browser Age Calculator
Exact age in years, months and days, and days until your next birthday.
Web tool · works in your browser- Premium
Word Counter
Count words, characters, sentences and paragraphs. Reading time, top keywords and word limits.
Web tool · works in your browser