RulerOnline
A free online ruler that calibrates to your screen's exact pixel density using a bank card, so on-screen measurements match real life.
Cost / License
- Free
- Proprietary
Platforms
- Online
Features
Properties
- Lightweight
Features
- Dark Mode
- No registration required
- Unit converter
RulerOnline News & Activities
Recent activities
- webtools6 added RulerOnline
webtools6 added RulerOnline as alternative to ScreenSize.net, Screen Ruler, ScreenRuler and KRuler
RulerOnline information
Developed by
webdeb limited Licensing
Proprietary and Free product.Alternatives
10 alternatives listedBadge
Get an embeddable badge for RulerOnlineSupported Languages
- English
What is RulerOnline?
RulerOnline is a free, no-login online ruler that measures real-world size directly on your screen. Most online rulers guess at your screen's pixel density and get the scale wrong — RulerOnline fixes this with a 10-second calibration step using a standard bank card (85.6mm wide under ISO/IEC 7810, the same size worldwide) or a sheet of A4 paper as a reference. Once calibrated, it remembers your screen for future visits.
Measure in millimeters, centimeters, or inches, with a dual-caliper "span" mode for measuring the distance between two points, full keyboard shortcut support, a measurement history log, and a printable ruler for offline use. Works in any modern browser, no installation or account required.