Measure angles in photos and with the camera
A practical method for aligning the center, both arms and the 3.5× lens accurately.
Read the complete guideOnline Protractor and Ruler Guides
Learn practical ways to measure angles and lengths on a screen, in images and on real objects.
Open the online protractor
Use the virtual protractor, 180°/360° modes, photo and camera.
Open protractorOpen the online ruler
Measure cm, mm, inches and pixels with calibrated screen edges.
Open rulerWhat you will learn
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How to use an online protractor with a photo or camera
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How to improve precision with the 3.5× lens and fullscreen mode
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When to use 180°, 360°, a protractor or a ruler
Updated: September 25, 2026