Display Calculators — PPI, Viewing Distance & Aspect Ratio

Display Calculators

Three quick reference calculators for display math: pixels per inch, recommended viewing distance, and aspect ratio simplification. Everything updates live as you type — nothing is sent anywhere.

These calculators use standard mathematical formulas, not device-specific measurements — results are approximations. The viewing-distance figures in particular are commonly-cited rules of thumb, not physiological guarantees or an industry standard. See notes under each result for details.

PPI & Pixel Pitch Calculator

Pixels per inch from resolution and diagonal size.

Horizontal resolution (px)

Vertical resolution (px)

Diagonal size (inches)

Pixels per inch (PPI)

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Diagonal pixels

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Pixel pitch (mm)

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diagonal_px = √(horizontal_px² + vertical_px²) · PPI = diagonal_px ÷ diagonal_inches · pixel pitch (mm) = 25.4 ÷ PPI

Viewing Distance Calculator

Rule-of-thumb distances for a given screen size and resolution.

Diagonal size (inches)

Resolution

Cinematic (THX-style) distance

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Comfortable range

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Pixel-invisible distance (20/20)

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"Cinematic" ≈ diagonal × 1.2 · "Comfortable" range ≈ diagonal × 1.6 to diagonal × 2.0 · "Pixel-invisible" distance uses the visual-acuity small-angle approximation: distance ≈ pixel_pitch ÷ tan(1 arcminute), where 1 arcminute (20/20 vision resolving limit) ≈ 0.0002909 radians. All three are commonly-cited rules of thumb (THX/SMPTE-style guidance), not physiological guarantees or a formal standard — actual comfortable distance varies by eyesight, content, and room.

Aspect Ratio Calculator

Simplify any width × height into its ratio.

Width (px or any unit)

Height

Simplified ratio

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Decimal ratio

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Common name

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Simplified via the Euclidean GCD algorithm: ratio = width÷gcd : height÷gcd. Non-integer inputs are scaled up to whole numbers first. "Common name" is the nearest standard ratio within a small tolerance, else "Custom".