PixelTools

PPI/DPI Calculator

How sharp a display actually looks, combining resolution with its physical size.

Width (px)

Height (px)

Screen diagonal (in)

Pixel density (PPI)

91.788

Higher PPI means sharper, crisper detail — most phone screens are 300+ PPI, most desktop monitors are 90-110 PPI.

What you entered

Width (px): 1920Height (px): 1080Screen diagonal (in): 24

1
Diagonal resolution in pixels
√(1920² + 1080²)= 2202.9072 px
2
Divide by physical diagonal size
2202.9072 ÷ 24 in= 91.7878 PPI

Result

Pixel density (PPI): 91.788

A 1920×1080 screen at 24" diagonal has a pixel density of 91.7877987534291 PPI.

Pixel density for common displays

PPI is the diagonal pixel count divided by the diagonal in inches. Around 110 PPI is comfortable on a desktop at normal viewing distance; phones run four times that because you hold them closer.

Resolution	Diagonal	PPI	Typical use
1920 x 1080	24 in	91.8	Budget desktop monitor
1920 x 1080	27 in	81.6	Noticeably coarse at 27 in
2560 x 1440	27 in	108.8	The desktop sweet spot
3840 x 2160	32 in	137.7	4K without scaling
3840 x 2160	27 in	163.2	4K, usually scaled
2532 x 1170	6.1 in	457.3	Modern phone

The same 1920x1080 panel drops from 91.8 to 81.6 PPI going from 24 to 27 inches, which is why a 27-inch 1080p monitor looks soft next to a 24-inch one.

Resolution alone doesn't tell you sharpness

The same 1920×1080 resolution looks noticeably sharper on a 24-inch monitor than stretched across a 55-inch TV — PPI captures that difference by factoring in the physical screen size, not just the pixel count.

PPI vs. DPI

PPI (pixels per inch) describes a screen's pixel density; DPI (dots per inch) technically refers to printers — the terms get used interchangeably in casual conversation, but this calculator specifically computes screen PPI.

Frequently asked questions

My 27-inch monitor is 2560x1440 — what's the PPI?

About 109 PPI. That's sharp enough for normal desktop viewing distances (2-3 feet). For comparison, a 27-inch 4K monitor hits about 163 PPI, and Apple's Retina standard targets 218+ PPI for laptops.

What PPI is considered 'Retina' or high-density?

Apple's 'Retina' label means pixels are indistinguishable at normal viewing distance — about 218+ PPI for laptops held at arm's length, and 300+ PPI for phones held closer. At typical desktop distance, 110+ PPI looks acceptable and 140+ looks sharp.

Is higher PPI always better?

For sharpness, yes, but with diminishing returns. Above ~300 PPI at normal phone viewing distance, the human eye can't distinguish individual pixels. Higher PPI also increases rendering workload and can make UI elements appear tiny without proper scaling.

How does this relate to the screen resolution calculator?

The screen resolution calculator gives you raw pixel count and megapixels from a resolution. This PPI calculator adds the physical screen size to tell you how sharp those pixels actually look — same resolution on a bigger screen means lower PPI.