What DPI should I use for mm to pixel conversion?

Use 96 DPI for standard web and CSS work, 72 DPI for legacy Mac references, 150 DPI for medium print, and 300 DPI for high-quality print.

MM to Pixels

Q: How do you convert mm to pixels?

Multiply the millimeter value by DPI divided by 25.4. At 96 DPI, 1 mm is about 3.7795 pixels.

Q: How many pixels is 1 mm?

It depends on DPI. At 96 DPI, 1 mm is about 3.7795 px. At 72 DPI it is about 2.8346 px, and at 300 DPI it is about 11.811 px.

Q: Can I convert pixels back to mm?

Yes. Divide pixels by DPI divided by 25.4. At 96 DPI, mm = px / 3.7795.

Q: Where does the 25.4 constant come from?

There are exactly 25.4 millimeters in one inch, so DPI can be converted into pixels per millimeter using that constant.

Q: How does DPI affect the conversion?

Higher DPI means more pixels per inch, so the same millimeter value converts to more pixels. The relationship is linear.

Q: How many pixels make 1 mm?

3.7795 pixels make 1 mm at 96 DPI (the CSS standard for web). At 72 DPI, 2.8346 pixels make 1 mm. At 150 DPI, 5.9055 pixels make 1 mm. At 300 DPI, 11.8110 pixels make 1 mm. The pixel count per millimeter equals DPI ÷ 25.4.

Q: What is mm to px?

mm to px is a unit conversion from millimeters to pixels based on display or print resolution. The conversion uses DPI (Dots Per Inch): px = mm × (DPI ÷ 25.4). At the web-standard 96 DPI, 1 mm = 3.7795 px.

Q: What is 10 mm in pixels?

10 mm = 37.7953 pixels at 96 DPI. At 72 DPI, 10 mm = 28.3465 pixels. At 150 DPI, 10 mm = 59.0551 pixels. At 300 DPI, 10 mm = 118.1102 pixels. The formula is: 10 × (DPI ÷ 25.4).

Q: What is 20 mm in px?

20 mm = 75.5906 px at 96 DPI. At 72 DPI, 20 mm = 56.6929 px. At 150 DPI, 20 mm = 118.1102 px. At 300 DPI, 20 mm = 236.2205 px. The formula is: 20 × (DPI ÷ 25.4).

Enter a value in either field — the other updates in real time. Adjust DPI for different screen/print resolutions.

Conversion Input

Real-time sync active

Millimeters (mm)

Pixels (px)

Screen DPI (Dots Per Inch)

Custom DPI Value

DPI

Decimal Precision

Conversion Result

37.7953 px

10 mm = 37.7953 px @ 96 DPI

Conversion Formula

px = mm × (DPI ÷ 25.4)

px = 10 × (96 ÷ 25.4)

px = 10 × 3.7795

px = 37.7953

Centimeters

1 cm

Inches

0.3937 in

Points (pt)

28.3465 pt

CSS rem (16px base)

2.3622 rem

How MM to Pixels Calculator Works

To convert millimeters (mm) to pixels (px), this MM to Pixels calculator applies 3 core steps: input a millimeter value, select a Dots Per Inch (DPI) setting, and multiply using the conversion factor.

Enter the mm value

Type any positive number in the millimeters field. The MM to Pixels calculator accepts whole numbers and decimals — for example, 0.5 mm, 10 mm, or 297 mm (A4 height).

Select the DPI

Choose a Dots Per Inch (DPI) value, also called Pixels Per Inch (PPI). Common presets include 72 DPI for legacy Mac displays, 96 DPI for standard web and CSS, 150 DPI for medium-resolution print, and 300 DPI for high-quality print output.

Read the pixel result

The calculator multiplies mm × (DPI ÷ 25.4) and displays the pixel count instantly. Results update in real time with a step-by-step formula breakdown, equivalent values in centimeters (cm), inches (in), points (pt), and CSS rem units.

The conversion factor 25.4 is the exact number of millimeters in 1 inch (25.4 mm = 1 in). This MM to Pixels calculator uses the same formula recognized by the World Wide Web Consortium (W3C) and referenced in MDN Web Docs: pixels = mm × (DPI ÷ 25.4). Rachel Andrew and Ethan Marcotte, two leading voices in responsive design, both reference this DPI-based relationship when discussing CSS unit conversion for web layouts.

Design tools including Adobe Photoshop, GIMP, and Figma use this same formula internally when converting between physical units (mm, cm, in) and pixel dimensions. The MM to Pixels calculator on this page mirrors that logic, so results match what designers see in professional graphic design software.

MM to Pixels Formula

The MM to Pixels formula is: pixels = mm × (DPI ÷ 25.4).

px = mm × ( DPI ÷ 25.4 )

This mm to px formula has 3 variables:

mm — the input distance in millimeters
DPI — the target resolution in Dots Per Inch (or Pixels Per Inch / PPI), such as 96 DPI for web or 300 DPI for print
25.4 — the fixed conversion factor, because 1 inch = 25.4 mm

MM to Pixels Formula Examples

10 mm at 96 DPI

px = 10 × (96 ÷ 25.4) px = 10 × 3.7795 px = 37.7953

10 mm at 300 DPI

px = 10 × (300 ÷ 25.4) px = 10 × 11.8110 px = 118.1102

25.4 mm at 96 DPI

px = 25.4 × (96 ÷ 25.4) px = 25.4 × 3.7795 px = 96 (exactly 1 inch)

The reverse formula to convert pixels to mm is: mm = px × (25.4 ÷ DPI). At 96 DPI, divide the pixel value by 3.7795 to get millimeters. At 300 DPI, divide by 11.8110.

In CSS, the W3C defines 1 px as exactly 1/96th of an inch, making 96 DPI the default reference pixel density for web design. Print designers using Adobe Photoshop or GIMP typically set resolution to 300 DPI or 150 DPI, producing different pixel counts for the same mm value.

MM to Pixels Conversion Chart

Reference chart showing mm to pixel values at 4 standard DPI settings. Use this MM to Pixels conversion chart for quick lookup without a calculator.

mm	px @ 72 DPI	px @ 96 DPI	px @ 150 DPI	px @ 300 DPI
0.5	1.4173	1.8898	2.9528	5.9055
1	2.8346	3.7795	5.9055	11.8110
2	5.6693	7.5591	11.8110	23.6220
3	8.5039	11.3386	17.7165	35.4331
5	14.1732	18.8976	29.5276	59.0551
10	28.3465	37.7953	59.0551	118.1102
15	42.5197	56.6929	88.5827	177.1654
20	56.6929	75.5906	118.1102	236.2205
25	70.8661	94.4882	147.6378	295.2756
50	141.7323	188.9764	295.2756	590.5512
100	283.4646	377.9528	590.5512	1181.1024
210	595.2756	793.7008	1240.1575	2480.3150
297	842.2677	1122.9921	1755.1181	3510.2362

The chart values above use the formula: pixels = mm × (DPI ÷ 25.4). Values for 210 mm and 297 mm correspond to A4 paper width and height — the most common paper size used in print design worldwide. At 300 DPI, an A4 page (210 mm × 297 mm) equals 2480 × 3508 pixels, a standard resolution for high-quality print output in Adobe Photoshop and Figma.

How Many Pixels to a mm

There are 3.7795 pixels in 1 millimeter at 96 DPI, which is the standard screen resolution for web browsers and CSS rendering defined by the W3C.

The number of pixels per millimeter changes based on the DPI (Dots Per Inch) or PPI (Pixels Per Inch) setting. There are 4 common DPI values and the corresponding pixels per mm for each:

2.8346

px per mm

@ 72 DPI

Legacy Mac / Web

3.7795

px per mm

@ 96 DPI

CSS / Windows Standard

5.9055

px per mm

@ 150 DPI

Medium Print

11.8110

px per mm

@ 300 DPI

High-Quality Print

Each pixel-per-mm value is calculated by dividing DPI by 25.4 (the number of millimeters in 1 inch). Higher pixel density means smaller individual pixels, which produces sharper images and text in print design and on high-DPI displays. The device pixel ratio on modern screens (such as Apple Retina displays) multiplies the CSS pixel count, making the physical pixel density even higher than the reference 96 DPI.

Web designers working with responsive design use the CSS px unit (1 px = 1/96 inch) for layout dimensions. Print designers working in GIMP, Adobe Photoshop, or Figma set their document to 300 DPI, producing 11.8110 pixels for every 1 mm of physical measurement.

Can You Convert MM to Pixels

Yes, you can convert MM to Pixels using the formula: pixels = mm × (DPI ÷ 25.4). The conversion requires a DPI (Dots Per Inch) value because millimeters are a physical unit of length and pixels are a digital unit tied to screen resolution or print resolution.

There are 5 common scenarios where you need to convert millimeters to pixels:

Web design — converting physical dimensions from print mockups into CSS pixel values at 96 DPI for viewport layouts and responsive design
Print design — setting image dimensions in Adobe Photoshop, GIMP, or Figma at 300 DPI for brochures, posters, and business cards
Document scanning — converting scanned document dimensions from MM to Pixels based on the scanner's DPI setting (150 DPI, 300 DPI, or 600 DPI)
CSS media queries — mapping physical measurements to px values for breakpoints in responsive web design, a technique championed by Ethan Marcotte
Digital image processing — calculating pixel dimensions for images destined for specific physical sizes in cartography, GIS applications, and engineering drawings

The MM to Pixels conversion is exact when DPI is known. At 96 DPI (CSS standard per the W3C), 10 mm = 37.7953 px. At 300 DPI (print standard), 10 mm = 118.1102 px. The conversion works in reverse too: divide px by (DPI ÷ 25.4) to convert pixels back to mm.

No software installation is required. This free online MM to Pixels converter handles bidirectional conversion (mm ↔ px), supports custom DPI values, and shows the step-by-step formula for each calculation.

MM to Pixels Calculators

MM to Pixels for Photoshop MM to Pixels for Illustrator MM to Pixels for InDesign MM to Pixels for Figma MM to Pixels for Canva MM to Pixels for Excel MM to Pixels for Procreate MM to Pixels for CSS MM to Pixels for JavaScript

Frequently Asked Questions

How do you convert MM to Pixels?

Multiply the millimeter value by (DPI ÷ 25.4). At the standard 96 DPI: pixels = mm × 3.7795. For example, 10 mm × 3.7795 = 37.795 pixels. The constant 25.4 comes from the fact that 1 inch = 25.4 mm.

How many pixels is 1 mm?

It depends on DPI. At 96 DPI (standard web): 1 mm ≈ 3.7795 pixels. At 72 DPI: 1 mm ≈ 2.8346 pixels. At 300 DPI: 1 mm ≈ 11.811 pixels. Our converter lets you choose any DPI for exact results.

What DPI should I use?

For web/CSS: 96 DPI is the standard reference. For Mac legacy: 72 DPI. For print (standard): 150 DPI. For high-quality print: 300 DPI. If you're doing front-end development, 96 DPI is almost always correct.

Where does the 25.4 constant come from?

There are exactly 25.4 millimeters in one inch. Since DPI measures dots (pixels) per inch, dividing DPI by 25.4 gives us the number of pixels per millimeter. This is a fixed, universally accepted conversion factor.

Can I convert pixels back to mm?

Yes! Divide pixels by (DPI ÷ 25.4). At 96 DPI: mm = pixels ÷ 3.7795. For example, 100 pixels ÷ 3.7795 ≈ 26.458 mm. Our converter works bidirectionally — type into either field and the other updates instantly.

How does DPI affect the conversion?

Higher DPI means more pixels per inch, which means more pixels per millimeter. At 300 DPI, 1 mm ≈ 11.81 pixels (great for print detail). At 72 DPI, 1 mm ≈ 2.83 pixels (lower resolution). The relationship is linear: doubling DPI doubles the pixel count for the same mm.

What is the difference between mm to px and MM to Pixels?

"px" is the standard abbreviation for "pixels." There is no mathematical difference — mm to px and MM to Pixels are the same conversion. Both use the formula: pixels = mm × (DPI ÷ 25.4). Whether you write px or pixels, the result is identical.

How many pixels make 1 mm?

3.7795 pixels make 1 mm at 96 DPI (the CSS standard for web). At 72 DPI, 2.8346 pixels make 1 mm. At 150 DPI, 5.9055 pixels make 1 mm. At 300 DPI, 11.8110 pixels make 1 mm. The pixel count per millimeter equals DPI ÷ 25.4.

What is mm to px?

mm to px is a unit conversion from millimeters to pixels based on display or print resolution. The conversion uses DPI (Dots Per Inch): px = mm × (DPI ÷ 25.4). At the web-standard 96 DPI, 1 mm = 3.7795 px. This mm to px conversion is used in web design, CSS, graphic design with Adobe Photoshop and Figma, and print production.

What is 10 mm in pixels?

10 mm = 37.7953 pixels at 96 DPI. At 72 DPI, 10 mm = 28.3465 pixels. At 150 DPI, 10 mm = 59.0551 pixels. At 300 DPI, 10 mm = 118.1102 pixels. The formula is: 10 × (DPI ÷ 25.4).

What is 20 mm in px?

20 mm = 75.5906 px at 96 DPI. At 72 DPI, 20 mm = 56.6929 px. At 150 DPI, 20 mm = 118.1102 px. At 300 DPI, 20 mm = 236.2205 px. The formula is: 20 × (DPI ÷ 25.4).