Calculate PPI, dot pitch, screen dimensions, aspect ratio, and total pixels for any display. Compare monitors, phones, and TVs with resolution presets.
Screen resolution, pixel density, and physical size are the three properties that define a display's visual quality. A 4K TV and a 4K phone have the same pixel count but vastly different pixel densities — the phone's pixels are packed far tighter, producing sharper images up close.
This calculator computes pixels per inch (PPI), dot pitch, physical screen dimensions, total pixel count, aspect ratio, and viewing distance recommendations from resolution and diagonal size. It supports custom resolutions and includes presets for common displays from phones to projectors.
Whether you're comparing monitors for design work, choosing a TV for your living room, evaluating phone displays, or calibrating print-to-screen workflows, this tool provides the display metrics that matter for your viewing distance and use case. It gives you a practical way to compare sharpness without relying on marketing terms like "retina" or "4K" alone. It also helps you judge whether the extra pixels are actually visible from where you sit.
Use this calculator when you want to compare displays by sharpness and usable screen area instead of relying on marketing labels alone. It is especially helpful for choosing between monitor sizes, TV resolutions, and phone displays at different viewing distances. That makes it easier to match resolution to the distance you actually sit from the screen.
PPI = √(w² + h²) / diagonal. Dot pitch = 25.4 / PPI mm. Physical width = (w / PPI) inches. Retina distance = 3438 / PPI arcminutes → inches. Aspect ratio = w:h (reduced by GCD).
Result: 163.2 PPI, 0.156 mm dot pitch, 23.5" × 13.2" active area
A 27" 4K (3840×2160) monitor has 163 PPI — sharp for desktop use at arm's length. Retina threshold ~21 inches (most people sit further).
Pixel density (PPI) determines how sharp a display looks at a given viewing distance. The human eye can resolve about 1 arcminute of detail — roughly 300 PPI at 12 inches, 150 PPI at 24 inches, or 60 PPI at 5 feet. Beyond this threshold, individual pixels are indistinguishable.
This is why phone screens are 400-600 PPI (viewed at 10-14"), desktop monitors are 100-220 PPI (viewed at 18-30"), and TVs are 40-100 PPI (viewed at 6-12 ft). Each makes sense for its typical viewing distance.
Standard HD (1080p): 1920×1080 — the workhorse resolution for general computing. QHD/1440p: 2560×1440 — the sweet spot for 27" desktop monitors. 4K/UHD: 3840×2160 — premium desktop/large TV resolution. 5K: 5120×2880 — Apple Studio Display, very high PPI at 27". 8K: 7680×4320 — future-proofing, minimal benefit at consumer TV sizes today.
The aspect ratio determines the shape of usable screen area. 16:9 wastes no space on widescreen video. 16:10 (1920×1200, 2560×1600) provides extra vertical space for documents, spreadsheets, and code — the visible difference is 11% more vertical content. 21:9 ultrawides (3440×1440) provide immersive gaming and replace dual monitors for productivity.
Apple's Retina standard is ~220 PPI at phone distance (12") or ~110 PPI at desktop distance (24"). The key is viewing distance: higher PPI is only beneficial if the viewer is close enough to see individual pixels.
27" 4K (163 PPI) is noticeably sharper than 27" 1440p (109 PPI) for text and fine detail at arm's length. For gaming, the added GPU load may not be worth it at that size.
4K (3840×2160) at 65" = 68 PPI. This is fine because TV viewing distance is typically 8-12 feet. You won't see pixel grid beyond ~8 ft at this PPI.
16:9 is standard for video. 21:9 ultrawide is great for productivity and cinematic content. 16:10 gives extra vertical space for documents. 4:3 maximizes area per diagonal.
PPI (pixels per inch) measures screen pixel density. DPI (dots per inch) measures printer/scanner resolution. They're often confused but technically different. For screens, PPI is correct.
Beyond the retina threshold for your viewing distance, additional PPI provides no visible benefit. Very high PPI also increases GPU workload and power consumption.