How to measure a reflex angle (360°)
Reflex angles are larger than 180°. The key is using 360° mode and deciding whether you need the interior angle or the outside (reflex) angle around the vertex.
When this helps
Use this when you need an angle that goes past 180° on a photo or diagram (for example, an outside corner). If your reading seems capped or flipped, it’s usually a mode/scale issue.
Step-by-step
- 1Switch to 360° modeEnable 360° mode before reading angles over 180°. This changes how the tool interprets the full turn.
- 2Align a clear baselineRotate/flip and use the grid to align one side direction so your 0° reference is stable.
- 3Place the center on the vertexZoom in and move the protractor center exactly onto the corner point where the two sides meet.
- 4Decide interior vs reflex, then readFirst identify the smaller interior angle (<180°) and the larger reflex angle (>180°). Read the one you actually need.
- 5Sanity-check and exportIf the value looks odd, re-check alignment and vertex placement. Export PNG/PDF or measurement data if you need to share it.
Tips
- If you can’t get a value over 180°, you’re not in 360° mode yet.
- Pick the angle first (interior vs reflex) so you don’t read the opposite side by accident.
- If snap makes the angle jump, try step snap (1°/5°/10°) or turn snap off for fine adjustment.
Related
Angle types (including reflex)
A quick reference for reflex angles and when to use 360° mode.
Angle between two lines
A clean workflow for diagrams when you’re measuring directions, not corners.
Alignment checklist
Reduce error by aligning the image before placing the vertex.
PNG and PDF exports
Save a shareable image or a report once you have the right reading.