Privacy Policy

How OnlineRuler handles information

OnlineRuler is designed to work in your browser. The ruler does not require an account, and measurement values are not submitted to this website.

Last updated: September 27, 2026

Information stored in your browser

The ruler may store calibration settings in your browser so the selected PPI and calibration method can be reused. The site also stores your light or dark theme preference locally. This information stays in your browser and is not sent to OnlineRuler by the application.

Information we do not request

OnlineRuler does not require registration and does not ask for your name, password, payment details, camera, microphone, location, or uploaded files. Values entered into the PPI calculator are used in the browser to calculate a result.

Hosting and links

Like most websites, the hosting provider may process standard technical request information, such as an IP address, browser type, and time of access, to deliver and protect the service. Third-party websites linked from OnlineRuler have their own privacy policies.

Your choices

You can remove locally stored settings by clearing this site’s browser data. If you have a privacy question or want to contact the site owner, visit our Contact Us page.

Policy updates

This policy may be updated when the website’s features or data practices change. The revised version will be published on this page with a new update date.

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.