360° mode
360° Protractor Online – Measure Reflex Angles
360° protractor online — the full circle protractor for 0° to 360°. Use it to measure reflex angles from 180° to 360° without swapping interior and exterior readings. Switch between 180° and 360° mode instantly — ideal for reflex angle protractor tasks and three-point angles on photos.
On the tool, tap 360° in the toolbar — or open with ?mode=360. You can switch back to 180° anytime.
Updated Online Protractor
Keyboard: Tab handles, arrows nudge 1px center / 1° ray (Shift 10px / 5°), R reset, G grid, L lock baseline, Z undo, Shift+Z redo, +/- zoom. Endpoint magnifier shows while dragging. Drag center, baseline ray, second ray. Snap preview before commit. Image stays local — never uploaded. Press Esc to exit fullscreen.
Camera stays local — capture is processed in your browser
Tip: also try Measure reflex angle in 180° mode — it makes the larger side primary without switching to 360°.
180° vs 360° — when to use which
Half-circle. The arc shows the inner angle ≤180° and the complement (360°−inner) as a secondary reading. Good for most classroom work.
Full circle. Both rays and the reflex arc are visible at once — no toggle needed for 270° or 300°.
Keyboard: press R to reset, S to cycle snap, arrows to nudge 1° (Shift 5°). See how to use and reflex angle.