Our Mission: True 1:1 Measurement Without Downloads
Everyone has experienced this dilemma: you need to quickly measure a bolt, credit card, coin, passport photo, or package, but no physical ruler or tape measure is anywhere in sight. Searching online for a "ruler image" produces unreliable results because static images cannot determine the physical size of your screen. A centimeter on a smartphone with 460 PPI is vastly different from a centimeter on a desktop monitor with 96 PPI.
Lineal Handy was created to solve this problem once and for all: a hardware-calibrated, high-precision online ruler that runs in any modern web browser. It is 100% free, requires no app installation, contains no ads, and demands no user registration.
How Real 1:1 Calibration Works
To render true physical centimeters, millimeters, or inches on a digital display, the software must determine the exact pixel density (PPI - Pixels Per Inch) of the connected monitor or mobile screen.
🪙1 Euro CoinStandardized diameter of 23.25 mm. Perfect for quick phone calibration.
💳Credit Card (ID-1)Worldwide ISO/IEC 7810 format (85.60 × 53.98 mm). Standard for desktop monitors.
📐Screen DiagonalEnter your known monitor diagonal in inches for instantaneous auto-calibration.
Once calibrated, our vector engine computes graduation lines to sub-pixel accuracy, guaranteeing exact physical sizing for all measurements.
Measurement Tools at Your Fingertips
📏 4-Edge Rulers
Turn on rulers along top, bottom, left, or right screen borders simultaneously or individually.
📐 2D Drag Caliper
Click and drag directly across the surface to measure between any two coordinates on the screen.
🎯 Crosshairs & Guidelines
Align objects with precision crosshair guides for repeatable inspections.
🌓 Fullscreen & Dark Mode
Expand to fullscreen to maximize measuring length with dark mode for visual comfort.
Our Core Principles
- Zero Friction: Free forever, zero advertisements, zero paywalls, zero accounts.
- Privacy-First: No analytics cookies, no user tracking, complete GDPR compliance.
- Universal Compatibility: Runs smoothly across iOS, Android, macOS, Windows, and Linux.
- Crafted with Pride: Clean typography and responsive design based on the modern Geist design system.
Questions or Feedback?We are constantly improving Lineal Handy and would love to hear from you.
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