Our Mission.
At Web Online Ruler, we believe everyday utilities should be simple, instantaneous, and respect user privacy. Traditional measuring tools require installing proprietary applications or granting camera permissions for estimation. We set out to create a web-based, 100% client-side online ruler that operates directly on any monitor, tablet, or phone display without any friction.
Whether you are a designer verifying UI layouts, a DIY enthusiast measuring a screw, or a student working on a project, we provide a clean, actual-size ruler calibrated to your screen dimensions.
Precision is Our Priority.
Screens vary wildly in size and resolution, meaning a generic image of a ruler will not show correct dimensions. To achieve pixel-perfect accuracy, Web Online Ruler relies on a comprehensive, hand-curated device hardware database.
When you visit our site, we inspect the screen resolution and user-agent data to match your hardware with known Pixels Per Inch (PPI) values. This enables our auto-detection system to scale the ruler precisely for popular iPhone, iPad, Samsung Galaxy, and notebook screens immediately.
ISO Standard Reference Objects
For devices that cannot be auto-detected, we implemented a custom Credit Card calibration. By aligning a physical card with our calibrated outline, we leverage the ISO/IEC 7810 ID-1 standard (exactly 85.60 mm wide) to calculate the precise pixel density of any custom display.
A Privacy-First Architecture.
We respect your digital footprint. Web Online Ruler operates entirely in your web browser.
- No Camera Required: We do not ask for camera or AR permissions, keeping your feed private.
- No Account Needed: No logins or registrations are required to use our tool.
- Local Storage only: Calibration numbers and theme settings are saved locally on your device (via
localStorage) and never uploaded to any server.