About Actual Size

Last updated: 2026-10-15

A free measuring tool, no account required.

Online Ruler is a small, independent project that gives you a ruler wherever you are — on your screen or on paper. It exists to solve a simple, everyday problem: you need to measure something right now and you don't have a physical ruler handy.

What you can do here

• On-screen ruler — measure objects, images and UI elements directly on your display. Calibrate it once against a real card (a credit card is 85.6 mm wide) and it becomes a true-size ruler.
• Printable ruler — download-free, print-at-100% rulers in centimetres, millimetres and inches that you can cut out and keep.
• Units and conversion — quick references and a converter between metric and imperial units.

Our approach

The tool runs entirely in your browser. Calibration is saved on your own device, not on our servers, so the experience stays private and works offline after first load. We keep the interface clean and free of clutter.

Accuracy note

Online Ruler is an everyday convenience, not a precision instrument. On-screen measurements depend on your display's actual pixel density and your calibration; always calibrate before relying on a measurement. For the printable ruler, print at 100% scale ("Actual Size") and disable "Fit to page".

Independent and ad-supported

This site is free to use. When advertising is enabled, it is supported by Google AdSense; until then the site runs ad-free. Advertising helps keep the tool available without paywalls. See our Privacy Policy for how advertising cookies work and your opt-out choices.

Get in touch

Questions, corrections or feedback? Visit our contact page.