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Free Measurement Tool

Online Protractor

Measure any angle by dragging three points. Switch between degrees and radians, enable 5° snap, load a background image, and export a PNG with the angle label included.

Snap 5°
Radians
Grid
Move all
Opacity
Stroke
Arms
Arc
Vertex
Grid
0°45°90°135°180°156.50°
156.50°

Drop or paste an image. Hold Space (or middle mouse) to pan. Use Ctrl/Cmd + wheel to zoom. Drag the three points to measure. Toggle Move all to reposition the whole protractor.

When Would You Actually Use an Online Protractor?

Geometry students are the obvious answer, but the use cases go much further. Architects and interior designers check roof pitches and staircase angles in scanned drawings. Woodworkers verify bevel cuts in photos match the intended angle. Photographers check the tilt of a horizon line. Teachers create angle measurement worksheets by exporting a PNG with the arc and label already visible. Anyone who has ever needed to verify "how steep is that slope, exactly?" has a practical use for a digital protractor.

For measuring physical distances rather than angles, the online ruler is the companion tool. If you need to measure pixel dimensions in a digital design, try the pixel ruler. And for unit conversions, the unit converter handles the rest.

Step-by-Step: How to Measure an Angle

  1. Optional — load an image: Click "Open image" or drag a photo, diagram, or screenshot onto the canvas.
  2. Place point B on the vertex — the corner of the angle. Drag A and C along the two rays extending from it.
  3. The angle between the rays appears live. Toggle between degrees and radians at any time.
  4. Enable Snap 5° to constrain to clean multiples of 5.
  5. Export PNG to save the measurement with the arc and label for reports or documentation.

Features

Frequently Asked Questions

A protractor is a tool for measuring or constructing angles. Physical protractors are usually semicircles with degree markings. This digital version works the same way but lets you drag points instead of aligning a physical tool.
Click "Open image" to load your photo or screenshot as a background layer, then drag points A, B, and C to align with the angle you want to measure. The reading updates live in degrees or radians.
Yes. Take a screenshot of the worksheet, upload it as a background, and measure each angle using the draggable points. Export a PNG to save your annotated result.
Yes. Toggle between degrees and radians using the unit switch in the toolbar. The canvas label updates immediately.
Yes. Use Export PNG to download an image with the angle arc and label, then print it at 100% scale. Or use your browser print dialog directly.
Yes. Enable "Snap 5°" to constrain measurements to multiples of 5 degrees — useful for presenting results or checking common angles like 30°, 45°, 60°, or 90°.