Pixels to Millimeters Converter

A millimeter (mm) is a common measurement unit but is not frequently used on CSS or print media. But, if a need arise that you to get the equivalent of px to mm, this Pixels to Millimeters Converter can be very handy.

For web, 1 inch is equal to 96 pixels. On the other hand, you should set this PPI value if you are working with digital or print designs. More information about PPI and DPI below.

How to Use Pixels to Millimeters Converter

What is PPI?

Pixels Per Inch or PPI, is used to measure how many pixels are there in one inch. For web-related designs/development, there are 96px in 1inch. However, if you are doing some photo editing work, the PPI (some call it DPI or Resolution) must be set to your desired output.

For example, you want a 200mm x 100mm image to be printed that looks the same on your design, you might want to set that PPI to 300ppi.

Pixels to Millimeters Conversion Table

Pixels Millimeters
37.8px 10mm
56.69px 15mm
75.59px 20mm
94.49px 25mm
113.39px 30mm
132.28px 35mm
151.18px 40mm
170.08px 45mm
188.98px 50mm
207.87px 55mm
226.77px 60mm
245.67px 65mm
264.57px 70mm
283.46px 75mm
302.36px 80mm
321.26px 85mm
340.16px 90mm
359.06px 95mm
377.95px 100mm
755.91px 200mm
1133.86px 300mm
1511.81px 400mm
1889.76px 500mm

How to Convert Pixels to Millimeters

Here are the conversions from World Wide Web Consortium:

Name Equivalence
millimeters 1mm = 1/10th of 1cm
inches 1in = 2.54cm
pixels 1px = 1/96th of 1in

So base on the unit conversions above, what we want to come up is that we want to get the equivalent of 1px to mm.

Considering that 1mm = 1/10th of 1cm, we can parse that value to get the inches:

1in = 2.54cm x 10 (*because there is 10mm in 1cm)

The result would be:

1in = 25.4mm

So base on the pixels conversion above, and the fact that 1 inch = 25.4 millimeters,

96px = 25.4mm

In other words,

1px = 25.4mm / 96

This yields to the result that 1mm is equal to 3.77952755906

Note: the 96px there is the Pixels Per Inch. In web, there are 96px in 1 inch. But in other screen and print media, you might need to set this to PPI value (ex: 300ppi)

Pixels to Millimeters Formula:

millimeters = pixels * ( 25.4 / PPI )

Note: If you are working with web or css, the default PPI is 96px.