Our Mission
We started Online Protractor Free with a simple frustration: the physical protractor is easy to lose, hard to read between tiny tick marks, and useless for photos or blueprints. Students hunt for a protractor before homework. Teachers struggle to project one clearly. Woodworkers approximate angles and waste material. We thought — the browser can do this better.
Our mission is to provide the best free online protractor — a digital protractor and virtual protractor that is instant, accurate to 0.1°, and completely private. No signup, no install, no image ever leaves your device.
What We Built
A fast HTML5 Canvas online protractor built for real use:
- 180° & 360° modes + 3-Point Finder — measure any vertex, from acute to reflex.
- 0.1° precision: per-degree snap, micro-nudges (-1°, ±0.1°, +1°), keyboard arrows & live HUD.
- Image workflow: upload JPG/PNG/WEBP or press Ctrl+V to paste a screenshot.
- Camera measure: capture any corner, roof pitch or miter joint — 100% local, nothing uploaded.
- Pro controls: 3× loupe, transparency, rotation, size & instant export (PNG/JPG/WEBP or copy).
Who It’s For
Homework & practice — angle types, complement/supplement. Works on whiteboards.
Drawings & site photos — verify angles without CAD.
Miter & bevel cuts — check 45°, 22.5° and custom slopes before you cut.
Logos & 3D models — measure any protractor image precisely.
Our Principles
- Private: Images & camera never leave your device. Privacy Policy.
- Fast: <1s load, offline-ready, 60fps on low-end devices.
- Accurate: 0.1° verified — not a toy.
- Free forever: No paywall, no signup.
Technology
Built for speed & privacy — static hosting on a global CDN, works offline after first load. No tracking. Dark mode via localStorage only.
Editorial & Accuracy Note
Guides are written and reviewed for accuracy. Found an error? Tell us — we fix verified issues within 48h.
Contact & Support
Small independent team. Reach us at onlineprotractorfree.com/contact-us — we read every message. Reply in 1–3 business days.