Complete guide to converting pixels to millimeters: how to accurately convert mm to pixels for screens and printing.

Understanding the relationship between pixels and millimeters is essential in design, printing, and display technology. Whether setting up an LED panel, designing a user interface, or preparing images for printing, knowing how to convert millimeters to pixels helps achieve accurate and consistent results.

This guide explains what "pixels in mm" means, how to calculate the conversion, and includes a mm-to-pixels conversion table that you can refer to whenever you need it.

Table of Contents

What does Pixel in Millimeter mean?

A pixel is a digital unit that represents a point of color on a screen or image. A millimeter (mm) is a unit of physical length. When we talk about pixels in millimeters or mm pixels, we are referring to the physical size that each pixel occupies in millimeters.

For example, if a pixel on your LED screen occupies 2.5 millimeters, the pixel pitch on the screen is 2.5 millimeters. This measurement directly impacts image sharpness; the smaller the value in millimeters per pixel, the sharper the screen.

Lower density in millimeters per pixel (e.g., 1.5 mm) – Higher resolution and better image detail.
High density of millimeters per pixel (e.g., 10 mm) Lower resolution, but good for viewing from a distance.

That's why an indoor LED screen might use a pixel pitch of 2.5 mm, while a large outdoor billboard might use 16 mm or more.

Why convert millimeters to pixels (mm to pixel)?

Converting millimeters to pixels (or mm to pixel) helps adapt digital designs to the physical dimensions of the screen. This ensures that your image or video fits correctly on the screen, without distortion or stretching.

Converting millimeters to pixels (or mm to pixel) helps adapt digital designs to the physical dimensions of the screen.
This ensures that your image or video fits correctly on the screen, without distortion or stretching.
Web design and user interface: matching real-world measurements with on-screen layouts.
Optical systems: aligning sensor resolution with lens dimensions.

By understanding the mm pixel unit of measurement, you will be able to communicate more precisely with manufacturers, printers, and engineers.

How to convert millimeters to pixels

The conversion depends on the device's resolution, usually expressed in DPI (dots per inch) or PPI (pixels per inch). The formula to convert millimeters to pixels is:

Pixels = Millimeters * (DPI / 25.4)

25.4 mm – 1 inch
DPI or PPI = number of pixels per inch

Example:

If your drawing is 50 mm wide and your monitor resolution is 96 DPI:

50 x 96 / 25.4 = 189 pixels

This means that your 50mm image is equivalent to approximately 189 pixels on a 96 DPI monitor.

Pixel to mm conversion formula

If you want to find out how many millimeters a pixel represents, you can reverse the formula:

mm = ( pixels * 25.4 ) / DPI

Example:

If you have 100 pixels on a 300 DPI printer:

100 x 25.4 / 300 = 8.47 mm

This means that 100 pixels are equivalent to 8.47 millimeters in length.

Conversion of standard pixels to mm (96 DPI reference)

Millimeter (mm)	Pixel (px)
1 mm	3.78 px
5 mm	18.9 px
10 mm	37.8 px
25 mm	94.5 px
50 mm	189 px
100 mm	378 px
500 mm	1,890 px
1000 mm (1 m)	3,780 px

This millimeters per pixel table uses 96 DPI (standard computer screen resolution). For higher DPI, such as 300 (used in printing), multiply by approximately 3.125 for more accurate results.

Converting millimeters to pixels at different DPIs

Millimeter (mm)	72 DPI (low resolution)	96 DPI (Default)	150 DPI (Medium)	300 DPI (high quality printing)
1 mm	2.83 px	3.78 px	5.91 px	11.81 px
10 mm	28.3 px	37.8 px	59.1 px	118.1 px
50 mm	141.7 px	189 px	295.5 px	590.6 px
100 mm	94.5 px	378 px	591 px	1,181 px

This shows how mm pixel values change depending on your device's resolution.

Pixel pitch and LED displays

Pixel Pitch (mm)	Pixels per meter (approx.)	Common use	Viewing distance
1.5 mm	666 px/m	Indoor environments, high resolution	1.5 – 3 m
2.5 mm	400 px/m	Indoor video walls	3 – 5 m
4 mm	250 px/m	retail, exhibitions	5 – 8 m
6 mm	166 px/m	external signage	8-12 m
10 mm	100 px/m	large billboards	12-20 m

Smaller pixel pitch values produce sharper images, but cost more. Pixels with wider spacing are more affordable and work well for viewing from a distance.

Practical uses of converting mm to pixels

LED display manufacturing: Engineers calculate the total number of pixels and the dimensions of the enclosure using pixel-in-millimeter data.
Fingerprint: Designers use millimeter-to-pixel conversion to set the correct file resolutions (e.g., 300 DPI).
Photography and scanning: Scanners rely on pixel values in millimeters to determine the accuracy of details.
Architecture and Industrial DesignAccurate mm-pixel conversion helps with scaling floor plans and visual renderings.

Quick conversion tips

Use 96 DPI for screen-based designs (nodes, digital ads, LED screens).
Use 300 DPI for printed materials (brochures, posters, packaging).
For LED displays, refer to the manufacturer's specifications for mm pixel (pixel pitch).
Always round pixel values to the nearest whole number to avoid layout changes.

Final considerations

Accurately converting millimeters to pixels helps control design accuracy, visual quality, and production consistency. Whether it's for a small digital banner or a huge LED panel, understanding pixel-to-millimeter conversion ensures the final result matches the desired scale and sharpness.

With the examples and mm-to-pixel tables above, you can confidently transition between digital and physical dimensions without guesswork.