Guide
How to Use the Online Protractor.
Learn how to measure angles on any image using our free online protractor tool. Step-by-step instructions for desktop and mobile.
Step 1: Upload an Image
Click the "Upload Image" button or drag and drop any image onto the canvas. You can also paste an image from your clipboard (Ctrl+V). Supported formats: JPG, PNG, GIF, WebP, SVG.
Step 2: Place Measurement Points
Click three points on the canvas: Point A (one ray of the angle), Point B (the vertex where the angle is measured), and Point C (the other ray). The protractor overlay helps you position them precisely.
Step 3: Read the Angle
The angle is calculated instantly. You will see the angle in degrees, the angle type (acute, right, obtuse, straight, reflex), plus the complementary and supplementary angles.
Step 4: Save or Share
Click "Save PNG" to download your measurement as an image. Perfect for including in reports, homework submissions, or sharing with your team.