Actual Size

About Actual Size

Last updated: 2026-10-17

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 centimeters, millimeters 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.

Editorial standards and sources

Content on Actual Size is written from publicly published standards rather than guesswork. The measurements built into the tools come from issuing authorities and standard-setting bodies, and are checked before publication:

  • Length units — the inch is defined as exactly 25.4 mm by the 1959 international yard and pound agreement; the metre and SI prefixes follow the BIPM / SI system.
  • Paper sizes — the A, B and C series follow ISO 216; US Letter and Legal are ANSI / North American conventions.
  • Everyday references — credit or debit card width (85.6 mm) follows ISO/IEC 7810 ID-1, and currency note sizes follow their issuing central banks (e.g. the European Central Bank for euro notes and the People's Bank of China for RMB).

We are an independent project and do not sell user data. If you spot a figure that looks wrong, the quickest route is the contact page.

Get in touch

Questions, corrections or feedback? Visit our contact page.