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Screen Resolution, PPI & Aspect Ratio Calculator

Built by Kevin Glover · @gloverbuilds · Verified formula

Calculate pixels per inch (PPI), aspect ratio, and total pixel count from screen resolution and size.

📅 Updated April 2026 ✅ Formula verified 📖 4 min read 🆓 Free · No sign-up

In this article

Understanding PPI (Pixels Per Inch)
Common Resolutions

Le PPI

PPI (pixels par pouce) = √(largeur² + hauteur²) ÷ diagonale. iPhone 15 (2556×1179, 6,1") : 460 PPI. MacBook Pro 14" (3024×1964) : 254 PPI. TV 65" 4K : 68 PPI. L'œil ne distingue plus les pixels au-dessus de ~300 PPI à distance de lecture. Pour les écrans de bureau : 100-120 PPI est confortable.

Ratios

16:9 : standard TV et moniteur. 16:10 : moniteurs productivité. 21:9 : ultrawide. 4:3 : ancien standard. 3:2 : Surface, certains Chromebooks. Pour le travail productif : le 16:10 est idéal (plus de hauteur verticale pour les documents).

⚡ CalcWolf Insight

The human eye can perceive approximately 300 PPI at 12 inches viewing distance — this is why Apple chose 326 PPI for the original Retina iPhone. At typical desktop viewing distances (24-30 inches), the equivalent is about 100-120 PPI. Buying a 5K monitor for a desktop you sit 3 feet from provides diminishing returns beyond bragging rights.

Frequently asked questions

Qu'est-ce qu'un bon PPI ?▾

Smartphone : 300+ PPI. Ordinateur portable : 200+ PPI. Moniteur de bureau : 100-120 PPI. TV à distance : 60-80 PPI suffit.

4K vaut-il le coup ?▾

Moniteur 27" : oui, différence visible. TV 55" à 3 m : à peine perceptible vs 1080p. L'impact dépend de la taille et de la distance.

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Kevin Glover · @gloverbuilds

Founder, CalcWolf · GLVTS · Blickr

All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →