About HeightCompare

Our Mission

Numbers on a page or numbers on a medical chart frequently fail to convey physical scale. When comparing heights—whether between family members, dating partners, athletes, fictional characters, or everyday household objects—our brains naturally understand spatial relationships through side-by-side visual comparison.

HeightCompare was created to provide a lightweight, 100% free, high-performance web tool that delivers mathematically accurate visual comparisons without bloated frameworks, invasive trackers, or mandatory user accounts.

Mathematical Precision & Proportionality

Unlike casual graphic tools that simply stretch or squash images vertically, HeightCompare uses an exact geometric coordinate model:

• Unit Normalization: Every measurement is converted to centimeters with sub-millimeter internal floating-point precision ($1\text{ in} = 2.54\text{ cm}$, $1\text{ ft} = 30.48\text{ cm}$).
• Shared Ground Plane: The bottom coordinate of every silhouette is locked to $Y_{\text{ground}} = 0$. This eliminates perspective distortion and visual parallax.
• Anatomical Scale Ratios: Silhouettes are designed according to physiological head-to-body ratios (adults at $\approx 1:7.5$ and children at $\approx 1:5.5$). Scaling factors are computed as $S = H_{\text{target}} / H_{\text{base}}$, maintaining natural anatomical posture.
• Calibrated Ruler: The measurement axis on the left reflects real-world metric (centimeters) and imperial (feet) divisions simultaneously.

Data Sources & Statistical References

All presets and comparative benchmarks provided in the application are derived from reputable scientific and epidemiological publications:

• World Health Organization (WHO): Child and adolescent growth standards, tracking 50th percentile physical height across development stages.
• NCD Risk Factor Collaboration (NCD-RisC): Worldwide adult height trends and pooled demographic health surveys across 200+ countries.
• CDC / National Center for Health Statistics (NCHS): National Health and Nutrition Examination Survey (NHANES) anthropometric reference data for U.S. adults.
• NBA Official Measurements: Official league pre-draft combine measurements (without shoes) for basketball players.

Privacy & Security Architecture

We believe utility tools should respect user privacy unconditionally:

• 100% Client-Side: All calculations, comparisons, and image generations run entirely inside your browser's JavaScript engine.
• No Server Database: We do not log, transmit, or store names or heights on any backend server.
• No Tracking Cookies: The application does not use tracking pixels, fingerprinting, or invasive analytics scripts.
• Local Persistence: Comparisons are saved exclusively on your own device using standard browser localStorage, which you can clear at any time with one click on the "Reset" button.

Engineering & Performance

Built according to modern web performance best practices:

• Vanilla JavaScript (ES6+): Zero heavy UI frameworks, resulting in sub-millisecond execution times and tiny bundle weight.
• Modular CSS Architecture: Native CSS variables, mobile-first media queries, zero cumulative layout shift (CLS = 0).
• Instant Execution: Works immediately without complex build steps, bundlers, or server runtimes.
• Accessible (WCAG 2.1 AA): Full keyboard operability, visible focus indicators, high contrast ratios, and semantic HTML elements.