Zellio.io

Angle Finder & Protractor

Measure angles with an interactive on-screen protractor.

Processed locally — nothing is uploaded

About Angle Finder & Protractor

Drag the arms across a photo, or over a physical object held against the display, and the reading updates live. Suits a roof pitch taken from a picture, a joint in a drawing, or any angle that would otherwise be estimated by eye.

Measure angles with an interactive on-screen protractor by dragging its arms over an image or object and reading the degrees live. It is useful for geometry homework, design layouts, woodworking references and any time you need to gauge an angle quickly.

Load a reference photo behind the protractor and drag the arms onto the angle you want to read. The readout updates as you move, so you can settle on the alignment rather than having to place it correctly first time.

Learn how this works

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Frequently asked questions

How do I measure an angle?

Drag the two arms of the protractor so they align with the angle you want to measure; the degree value updates live as you move them. Position one arm along a reference line or edge, then rotate the other arm to align with the second line you're measuring. The degree display updates continuously as you drag, so you can fine-tune the measurement with pixel-level precision. Once aligned, the angle is displayed in degrees, making it useful for geometry, construction, design, and any application requiring angle measurements.

Can I measure angles on my own image?

Yes — the protractor overlays on screen so you can line it up against an image or object and read the angle directly. Upload any image to the tool or display a photo on your screen, then overlay the interactive protractor on top and align its arms to the lines or edges you're measuring. This is useful for analyzing angles in photos, diagrams, construction plans, or design layouts. Since everything runs in your browser, your images stay private and the measurements are instant.

Is it free?

Completely. There is no sign-up, no account, no watermark and no usage limit. The tool is supported by unobtrusive ads, not by selling or processing your data.

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Angle Finder & Protractor

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