Screen PPI calculator

How sharp is your screen?

Enter the resolution and screen size to get pixels per inch, dot pitch and the physical size of the display.

Width in pixels

Height in pixels

Screen diagonal

Diagonal unit

Pixel density

91.8 PPI

On a 1,920 × 1,080 screen that size, neighbouring pixels are 0.277 mm apart

More about the screen

Pixels per centimetre: 36.1 px/cm
Dot pitch: 0.277 mm
Screen size: 20.92 × 11.77 in (53.1 × 29.9 cm)
Aspect ratio: 16:9
Total pixels: 2.07 megapixels

How to use

Type the screen's resolution in pixels, such as 1920 by 1080.
Type the screen's diagonal size and pick inches or centimetres. The pixel density appears at once.

Pixel density of common monitor sizes

Diagonal (in)	Resolution (px)	PPI
24	1,920 × 1,080	91.8
27	1,920 × 1,080	81.6
27	2,560 × 1,440	108.8
27	3,840 × 2,160	163.2
32	3,840 × 2,160	137.7

How it works

Pixel density says how many pixels fit along one inch of the screen. More pixels per inch means finer detail and smoother text; fewer means you can see the individual pixels from close up. It is a property of the screen itself, so a small phone and a large TV with the same resolution have very different densities.

PPI = √(width² + height²) ÷ diagonal, with the width and height in pixels and the diagonal in inches. The square root is Pythagoras: it gives the diagonal in pixels. For example, 1920 × 1080 on a 24-inch screen is √(1920² + 1080²) ÷ 24 = 2202.9 ÷ 24 = 91.8 PPI. The dot pitch is the gap between neighbouring pixels: 25.4 mm ÷ PPI, which here is 0.277 mm (an inch is exactly 25.4 mm).

The calculation assumes square pixels, which is true of almost every modern display. The diagonal is the visible one a maker quotes, rounded; a screen sold as 27 inches may measure a little differently, so the result is a good estimate rather than a precise measurement.

Frequently asked questions

What is a good PPI?

It depends on how far away you look at the screen. The closer you are, the more pixels per inch you need before the pixels disappear: a phone held in the hand needs far more than a TV across the room.

Is PPI the same as DPI?

Not quite. PPI counts pixels on a screen; DPI counts ink dots of a printer. People often mix them up, but the maths for a screen is the PPI formula above.

What is dot pitch?

The distance between the centres of neighbouring pixels, in millimetres. A smaller dot pitch means a sharper picture.

Does a bigger resolution always mean a sharper screen?

No. Sharpness depends on the resolution relative to the size: 4K on a 32-inch monitor has a lower PPI than 4K on a 27-inch one.

Should I include the bezel in the diagonal measurement?

No. Measure only the visible screen from one corner to the opposite corner, not the frame around it.

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