画素密度 (PPI) 計算機
解像度と画面サイズから画素密度（PPI）、ドットピッチ、表示の精細度を瞬時に算出します。
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Resolution Presets
Screen Details
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Total Pixels
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Megapixels
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Pixel Size
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PPI Reference by Device Type
| Device | Typical PPI | Retina Threshold | Viewing Distance |
|---|---|---|---|
| Phone | 400–500+ | 300+ PPI | 10–14" |
| Tablet | 250–330 | 260+ PPI | 14–18" |
| Laptop | 130–260 | 200+ PPI | 16–22" |
| Monitor | 90–220 | 140+ PPI | 20–30" |
| TV | 40–100 | N/A | 5–15 ft |
The Formula
PPI = √(W² + H²) ÷ diagonal
where W = horizontal pixels, H = vertical pixels