About Us — True Scale Ruler (1:1 Screen Measurement Story)

Our Mission

We built True Scale Ruler to solve a fundamental flaw in modern digital computing: web browsers have never known the real physical dimensions of your display. Our mission is to transform any screen—from mobile phones to ultrawide workstations—into an authentically calibrated, contact-safe measurement instrument.

1. The Problem: The "96 CSS Pixels Per Inch" Myth

In the early days of personal computers, cathode-ray tube (CRT) monitors typically operated at approximately 72 to 96 pixels per inch (PPI). The World Wide Web Consortium (W3C) formalized this assumption in CSS specifications by defining 1in = 96px.

However, modern technology has vastly outpaced that 1990s standard:

A 6.1-inch smartphone display often features over 460 physical pixels per inch.
A 14-inch laptop Retina display packs 250+ physical pixels per inch.
A 27-inch 1440p gaming monitor operates around 108 physical pixels per inch.

When an ordinary website draws a line of "100 pixels" or "1 inch", it is completely distorted. On a smartphone, it appears microscopic; on a large monitor, it appears oversized. Traditional online rulers were little more than static images that could not measure anything accurately in real life.

2. The True Scale Solution: Real-World Object Calibration

Because web security prevents browsers from directly probing your monitor's internal tape measure, True Scale Ruler employs an elegant, mathematically sound approach: optical reference synchronization.

Globally, credit cards, bank debit cards, driver's licenses, and government identity cards follow the strict ISO/IEC 7810 ID-1 standard: exactly 85.60 mm wide by 53.98 mm high (3.370 × 2.125 inches). By asking you to align an on-screen slider with a real card for just three seconds, True Scale Ruler calculates your screen's precise sub-pixel hardware pitch down to hundredths of a millimeter.

3. The 5-in-1 Precision Measurement Architecture

True Scale Ruler is designed not as a toy, but as a full-featured digital workbench for students, makers, 3D printing enthusiasts, designers, and craftsmen:

Sliding Digital Caliper Jaws: Independent Jaw A (zero baseline) and Jaw B (reading indicator) with single-pixel nudge keyboard controls ([A]/[D] and arrow keys) for effortless micro-measurements.
Dual-Scale 12" & 30cm Ruler: Instant toggles between metric (cm & mm ticks) and imperial fractional markings (down to 1/32" of an inch).
360° Rotating Protractor: Semicircle (180°) and full circle (360°) modes with 15°, 30°, 45°, and 90° angle snapping.
Jewelry Ring Sizer: International sizing diameter circles for US, UK, EU, and Japanese standards.
2D Bounding Box Area Tool: Live surface area and perimeter calculations for shipping envelopes, packages, and hardware parts.
Touchscreen Freeze Lock: Tap the Lock icon to freeze all ruler positions, enabling users to place physical pens, screws, or cards directly against their touchscreen without unwanted panning or zooming.

4. Architectural Philosophy: Linear Obsidian Design

We believe utility software should be as beautiful as it is functional. Inspired by modern developer workspaces (such as Linear.app), True Scale Ruler features deep obsidian canvas backgrounds (#0B0D13), soft backdrop blurs (rgba(18, 22, 31, 0.85)), hairline borders, and JetBrains Mono tabular coordinate readouts that eliminate horizontal layout shift.

5. 100% Client-Side & Privacy-First