Terms and Conditions

Terms for using OnlineRuler

These terms explain the basic conditions for using the free online ruler, screen measurement tools, calibration features, and related pages on this website.

Last updated: September 27, 2026

Use of the website

You may use OnlineRuler for lawful personal, educational, design, craft, office, and everyday measuring tasks. You are responsible for having permission to measure or handle any object you place beside the screen.

Measurement accuracy

Measurements shown by an online ruler are estimates until the screen is calibrated. Display size, pixel density, browser zoom, operating-system scaling, device orientation, and other settings can affect the result.

Do not rely on OnlineRuler as the only measurement source for safety-critical, medical, legal, construction, manufacturing, or other situations where exact physical accuracy is required. Verify important measurements with a suitable physical instrument.

Availability and changes

We may update, improve, restrict, or discontinue a feature of the website at any time. We aim to keep the service useful and available, but we do not promise uninterrupted operation or that every device and browser will behave identically.

Content and links

OnlineRuler’s design, text, branding, and software belong to the site owner unless stated otherwise. You may not copy, misuse, disrupt, or attempt to gain unauthorized access to the website. Links to other websites are provided for convenience and are governed by those websites’ own terms.

Questions about these terms

If you have a question about these terms or the use of the website, please visit Contact Us. These general website terms do not replace professional legal advice or any rights that apply under your local law.

Helpful answers

Online ruler FAQ: how to use a ruler online

Find quick answers about using a free online ruler, measuring in inches or millimetres, and calibrating your screen for an actual-size result.

How to use an online ruler?

To use an online ruler, open OnlineRuler, choose cm, mm, inches, or pixels, and place your object against a screen edge. Read the live marker as you move across the scale, then calibrate the display when you need an actual-size result.

Is there a ruler online?

Yes. OnlineRuler is a free online ruler that works in a browser on desktops, laptops, tablets, Android devices, and phones. This ruler online needs no download, registration, or account.

Can I use my phone as a ruler?

Yes, you can use your phone as a ruler by opening OnlineRuler in a mobile browser. It works as a ruler for phone or iPhone measurements; place the object beside the scale and calibrate for better accuracy.

How to measure cm online?

Select cm in the ruler controls, align the object with the top, bottom, left, or right edge, and follow the centimetre markings. Calibrate the screen first if an online ruler cm measurement must match the physical size.

How to identify 1 inch?

Switch the tool to inches and use the numbered marks: the distance between consecutive whole-number marks is one inch. For an accurate online ruler inches measurement, calibrate your display before measuring a physical object.

How to read a ruler online?

Choose the unit you need, then read the numbered major marks and the smaller divisions between them. This online ruler shows inches, millimetres, centimetres, or pixels, including an online ruler inches vertical scale when the side edge is selected.

Can we measure online?

Yes, you can measure online using a screen ruler for layouts, crafts, schoolwork, and everyday objects. It is an accurate online ruler after calibration, while uncalibrated measurements are estimates based on your display.

Can a smartphone measure?

A smartphone can measure small objects with a ruler for phone screen, but screen size and pixel density affect the result. Use an Android ruler or ruler for iPhone in the browser, then calibrate it for a more accurate measurement.

Can I use my camera as a ruler?

This online ruler uses the visible screen scale rather than the camera, so no camera access is needed. For a reliable result, place the object beside the ruler and calibrate the screen instead of estimating size from a photo.

How to view or add a ruler in Word Online?

In Word Online, open the View tab and turn on Ruler when the option is available in your version. For a quick on-screen measurement outside the document, use this free online ruler and choose cm, mm, or inches.

How to show a ruler in PowerPoint Online?

Open the View tab in PowerPoint Online and enable Ruler if it is available in the web editor. When you need to check a physical size or screen distance, use the calibrated online ruler alongside your presentation.