Design Tools
Online Ruler
🔒 Runs in your browser
Calibrate your screen and measure objects on-screen in centimetres or inches using your display as a ruler.
Click anywhere on the ruler to place a measurement marker. Enter your screen's diagonal size above for accurate measurements.
How to Use an Online Ruler — Free Screen Ruler (2026)
Measure objects on your screen with pixel-accurate precision using a free online ruler. Enter your screen diagonal to calibrate, then click to place measurement markers.