About Us
Last updated: 14 August 2026
Online Free Ruler is a free, accurate measuring tool that turns any screen into a real, actual-size ruler. We built it so anyone can measure in inches, centimeters, and millimeters instantly — without hunting for a physical ruler, installing an app, or creating an account.
Questions, feedback, or corrections
support@onlinefreeruler.comWhat We Do
Our online ruler shows true-to-scale markings in your browser and calibrates to your specific screen, so one on-screen centimeter equals one physical centimeter. You can place rulers on any edge, drag to measure distances, drop guides, and switch between cm, inches, and pixels in a click.
Why We Built It
Most on-screen rulers ignore the fact that every display has a different pixel density, which makes their measurements little more than guesses. We wanted a genuinely accurate online ruler that respects your privacy, loads instantly, and works the same on a phone, tablet, or desktop.
Our Principles
We keep the tool fast, clean, and free, with no sign-ups. The ruler itself runs locally in your browser, and your calibration is saved only on your own device. We use Google Analytics to understand overall traffic to the site, as described in our Privacy Policy. We are committed to accessibility, so the ruler works with a keyboard and screen readers too.
Founder & Maintainer
Online Free Ruler is created and maintained by Shebaz Qureshi, its founder and maintainer. Shebaz is an Automation Architect with more than 15 years of experience architecting software quality for enterprise clients, including long-term onsite engagements in the United States. Precision and verification are at the core of everything he builds — the same principles behind this tool.
How the Tool Works
The ruler displays scale markings in your browser and can be calibrated to your specific screen, so an on-screen centimeter is intended to match a physical centimeter. It includes rulers on different screen edges, a distance-measurement mode, guides, and unit choices for centimeters, inches, millimeters, and pixels.
Accuracy and Its Limits
Screens differ in size, resolution, scaling, and browser settings. For that reason, the tool asks you to calibrate it using a known-size object, a supported device profile, or your screen dimensions. Calibration can make the ruler useful for everyday measurements, but results still depend on your display and the calibration you provide.
Online Free Ruler is intended for general, non-critical use. Do not use it as the sole measuring method for medical, safety, legal, engineering, manufacturing, or other high-precision work. Where an exact measurement matters, confirm the result with an appropriate certified physical measuring instrument.
Quality, Accessibility, and Corrections
We work to keep the tool useful, quick to load, and understandable on phones, tablets, and desktop computers. We test updates in supported modern browsers and aim to make controls usable with a keyboard and assistive technology. If a measurement, page, translation, or accessibility feature is unclear or incorrect, email support@onlinefreeruler.com with your device, browser, and a short description so we can investigate and correct it where appropriate.
Privacy and Responsible Operation
The core ruler runs in your browser. Its calibration setting, preferred unit, and theme are stored locally on your device so your preferences can persist between visits. Our Privacy Policy explains our current analytics use, cookies, and third-party services; please review it for the latest details.