Online Protractor
Drag two arms around a movable vertex to measure any angle on your screen — for geometry, design, woodworking, or a photo you upload. Instant, accurate, and 100% private.
How to Measure Angles Online
ToolsPix Online Protractor is a free, interactive protractor that lets you measure any angle right in your browser. It is drawn with lightweight SVG and the browser's own geometry, so there is no software to install, no account to create, and nothing is ever uploaded to a server.
Why use ToolsPix Online Protractor?
- Completely free with no sign-up, watermark, or usage limit.
- Runs entirely in your browser — any photo you load stays on your device.
- Drag two independent arms around a movable vertex to measure any angle.
- Switch between 0–180° interior angles and a full 0–360° sweep, including reflex angles.
- Works with mouse, touch, and keyboard, on phones, tablets, and desktops.
Steps to measure an angle
Drag the centre handle onto the corner (vertex) of the angle you want to measure, then drag each arm handle along the two sides of the angle. Read the result in the live readout below, switch to 0–360° if you need a reflex angle, and use Upload image to measure angles on a photo. Press Reset to start over. Once the page is loaded, the tool also works completely offline.
FAQ
How do I measure an angle with the online protractor?
Place the centre handle on the angle's vertex, then drag the two arm handles along each side of the angle. The reading at the bottom updates live, showing the angle between the arms to one decimal place.
How accurate is the angle measurement?
The angle is calculated geometrically from the exact on-screen positions of the two arms and shown to one decimal place (0.1°). In practice, accuracy is limited only by how precisely you place the handles on the angle you are measuring.
Can I measure angles on my own photo or image?
Yes. Use Upload image to load a photo behind the protractor, then drag the arms onto the angle you want to measure — for example a roof pitch, a joint, or a printout. The image stays on your device and is never sent to any server.
What is the difference between 0–180° and 0–360° mode?
0–180° mode shows the smaller interior angle between the two arms, which is what you need for most geometry. 0–360° mode measures the full sweep clockwise from the first arm to the second, so it can also report reflex angles above 180°.
Is the online protractor free and is my image uploaded anywhere?
The protractor is completely free with no sign-up. Everything runs locally in your browser with JavaScript, so any image you load and every measurement you take stays on your device and is never uploaded.