PixelSizes

Screen tools

Screen PPI Calculator

Calculate display pixel density, physical width and height, and pixel pitch from the native resolution and screen diagonal.

Your dimensions

On your device

Illustrative combinations, not specifications for a particular device. Enter your display’s actual measurements below.

Use panel pixels, not a scaled browser viewport.

Use the panel’s native pixel dimensions.

Measure the display area, excluding its bezel.

Use the same unit as the diagonal you entered.

Use a decimal point, without commas. Physical lengths and PPI accept up to 4 decimal places.

Example result

91.79 PPI

1,920 × 1,080 native pixels · 24 in diagonal

Display width × height
20.92 × 11.77 in
Metric dimensions
53.13 × 29.89 cm
Pixel pitch
0.2767 mm
Display proportionsNative pixel area · proportions only
Illustrative geometry · proportions, not actual screen size

Use the display’s native pixel grid and viewable diagonal, excluding its frame.

CSS defines a relationship of 96 CSS px per CSS inch. That relationship is not a measurement of this screen’s physical pixel density.

Calculation details & inputs
Inputs used for this result
Horizontal native resolution1920 px
Vertical native resolution1080 px
Viewable screen diagonal24
Diagonal unitInches (in)
Result details · 6 decimals or 3 significant digits for tiny values
Pixel density (PPI)91.787799
Width (in)20.917813
Height (in)11.76627
Width (cm)53.131245
Height (cm)29.886325
Pixel pitch (mm)0.276725
Megapixels2.0736

Behind the numbers

How the calculation works

Screen PPI = √(horizontal pixels² + vertical pixels²) ÷ diagonal inches.

Assumes a rectangular flat display with square pixels. Browser CSS pixels, operating-system scaling and devicePixelRatio do not establish the physical screen size.

Results use the numbers you enter. See the methodology for precision, accepted ranges and sharing behavior.

Reference notes

References checked September 28, 2026. Calculations and worked examples are our own.

Useful answers

Common questions

Can the browser detect my physical screen PPI?

Native panel resolution and viewable diagonal are needed. Browser viewport dimensions and devicePixelRatio describe layout or scaling behavior and are insufficient to establish physical dimensions. Enter your display’s actual specifications.

Are the presets specifications for particular monitor models?

No. They are illustrative resolution-and-diagonal combinations. The density is calculated from those inputs. A manufacturer may use a nominal diagonal; measured panel dimensions can differ.

Is a 27-inch 4K screen always 163.18 PPI?

A rectangular square-pixel panel with a 27-inch viewable diagonal and 3840 × 2160 native pixels calculates to about 163.18 PPI. A different meaning of 4K, a different actual diagonal or another pixel geometry changes the result.

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