How to measure an angle on a screenshot

This is the fastest workflow when you already have the angle on your screen: take a snip, paste it into the tool, align, then read the angle.

Open the tool Back to Tutorials

Take a clean snip

Paste into the tool

Align one side as your baseline

When this helps

Use this for screenshots from videos, websites, CAD drawings, textbooks, or any on-screen diagram. If the screenshot is blurry or low-res, zoom in before you capture it.

Step-by-step

1
Take a clean snip
Capture just the region around the angle. Include a bit of straight edge on each side so alignment is easier.
2
Paste into the tool
Open the tool and paste the screenshot (Ctrl/⌘+V). You can also upload the image if you prefer.
3
Align one side as your baseline
Use rotate/flip, the grid, and brightness/contrast so one side direction is stable and easy to follow.
4
Place the vertex and pick the right mode
Move the protractor center to the vertex. Use 180° for interior angles; switch to 360° if you need an angle over 180°.
5
Read and export
If the reading looks off, re-check baseline alignment and vertex placement. Export PNG/PDF or the measurement data when it matches.

Tips

Bigger screenshot = better accuracy. Zoom in before you capture.
Use Snap for clean targets (30°/45°/90°) and turn it off for the last 1–2° if needed.
If the value keeps jumping, check snap mode (common vs step) and re-align the baseline.

Measuring from a PDF? Use the PDF screenshot workflow

Measure an angle on a photo

A general workflow for any image: align, place the vertex, then measure.

Alignment checklist

If the screenshot reading looks wrong, start with alignment.

Snap not working

Fix snapping issues and learn when to turn snap off.

PNG and PDF exports

Save a shareable image or a report once you have the right angle.

How to measure an angle on a screenshot

When this helps

Step-by-step

Tips

Related