Online Ruler is a small set of free measuring tools that run in your browser. We built them because most screen rulers guess the size of your display and get it wrong.
Our ruler asks you to calibrate once with an object everyone has, a bank card, or with your device model. From then on it shows real centimeters, millimeters and inches on that screen.
- No sign-up. Every tool works without an account.
- Private. Your settings stay in your browser. Nothing is uploaded.
- Honest. We tell you when a reading is an estimate and when it is calibrated.
Tools: Online Ruler, Inch Ruler, CM Ruler and the Screen Size Calculator. Questions or ideas? Contact us.