MM to PX for CSS

Convert CSS millimeters to CSS reference pixels using the fixed 96 PPI relationship.

CSS dimensions

Width (mm)

Height (mm)

CSS reference resolution

PPI

Decimal precision

CSS output

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Width

—

Height

—

Points

—

Megapixels

—

CSS output

CSS defines 1in as 96px and 1in as 25.4mm, so 1mm equals about 3.7795px.

How MM to PX for CSS Works

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Enter the mm value

Type the millimeter value you want to convert to CSS pixels.

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Fixed CSS ratio

The CSS specification defines 1in = 96px = 25.4mm. This ratio is always constant.

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Get the CSS output

The calculator shows the pixel value and generates a ready-to-use CSS declaration.

The CSS specification defines absolute length units with a fixed relationship: 1 inch equals exactly 96 CSS pixels and 25.4 millimeters. This means 1 mm is always 96 ÷ 25.4 ≈ 3.7795275591 CSS pixels. This ratio never changes regardless of the physical display — CSS pixels are logical units that the browser maps to device pixels using the device pixel ratio.

MM to PX for CSS Formula

px = mm × 3.7795275591 Conversion Formula

The CSS specification defines this exact relationship: 1in = 96px = 25.4mm. The conversion factor 96 ÷ 25.4 = 3.7795275591 is a fixed constant in all browsers.

1 mm

1 × 3.7795
= 3.7795 px

10 mm (1 cm)

10 × 3.7795
= 37.7953 px

25.4 mm (1 in)

25.4 × 3.7795
= 96 px

Reverse Formula

mm = px ÷ 3.7795275591

MM to PX for CSS Conversion Chart

CSS mm-to-px conversions at the fixed 96 PPI reference. These values are identical across all modern browsers.

mm	72 PPI	96 PPI	150 PPI	300 PPI
1 mm	2.8346	3.7795	5.9055	11.8110
2 mm	5.6693	7.5591	11.8110	23.6220
3 mm	8.5039	11.3386	17.7165	35.4331
5 mm	14.1732	18.8976	29.5276	59.0551
10 mm	28.3465	37.7953	59.0551	118.1102
15 mm	42.5197	56.6929	88.5827	177.1654
20 mm	56.6929	75.5906	118.1102	236.2205
25 mm	70.8661	94.4882	147.6378	295.2756
50 mm	141.7323	188.9764	295.2756	590.5512
100 mm	283.4646	377.9528	590.5512	1181.1024