PX to MM Converter

Convert pixels to millimeters easily with our PX to MM converter. Perfect for designers and developers needing accurate measurements.

Pixels (PX) to Millimeters (MM)

We’re assuming a standard screen resolution of 96 DPI (dots per inch).

PixelsMillimeters
1px0.2646mm
2px0.5292mm
3px0.7938mm
4px1.0584mm
5px1.323mm
6px1.5876mm
8px2.1168mm
10px2.646mm
12px3.1752mm
14px3.7044mm
15px3.969mm
16px4.2336mm
18px4.7628mm
20px5.292mm
24px6.3504mm
25px6.615mm
28px7.4064mm
32px8.4672mm
36px9.528mm
40px10.584mm
44px11.6448mm
48px12.7008mm
50px13.23mm
56px14.8224mm
64px16.9344mm
72px19.0512mm
75px19.845mm
80px21.168mm
90px23.7492mm
100px26.46mm

Millimeters (MM) to Pixels (PX)

MillimetersPixels
1mm3.7795px
2mm7.5591px
3mm11.3386px
4mm15.1181px
5mm18.8976px
6mm22.6772px
7mm26.4567px
8mm30.2362px
9mm34.0157px
10mm37.7953px
12mm45.3543px
14mm52.9134px
15mm56.6929px
16mm60.4724px
18mm68.0315px
20mm75.5905px
22mm83.1496px
24mm90.7087px
25mm94.4882px
28mm105.652px
30mm113.385px
32mm120.944px
36mm135.590px
40mm150.236px
44mm164.882px
48mm179.528px
50mm188.976px
56mm211.811px
64mm242.519px
72mm273.228px
75mm284.646px
80mm302.283px
90mm340.157px
100mm377.953px

What are PX in CSS?

In CSS, PX (pixels) is an absolute unit of measurement used to define the size of elements. Unlike relative units such as EM and REM, PX provides fixed, non-scaling values that don’t change relative to the parent or root element. Here’s a breakdown of PX and its use cases:

Definition of PX:

  • Pixels (PX): A pixel is a unit that corresponds to a single dot on a computer screen or display. In CSS, 1px represents one pixel of the display, regardless of screen resolution or size.
  • Fixed Size: Unlike EM and REM, which are relative units, PX is an absolute unit, meaning it sets a fixed size for an element, regardless of the context or surrounding elements.

Characteristics of PX:

  1. Absolute Measurement: PX provides an absolute value, meaning the size set using PX will remain the same, regardless of the surrounding environment or context (like parent elements).
  2. Non-Responsive: Since PX is an absolute unit, it doesn’t scale automatically based on the user’s screen size, resolution, or browser settings. For responsive designs, PX is often less flexible than relative units like REM or percentages.
  3. Precise Control: PX gives designers exact control over the sizing of elements. If you need a specific size, regardless of other factors, PX is a reliable option.
  4. Device-Dependent: While PX is considered an absolute unit, its actual size may vary slightly across devices with different screen densities (e.g., standard displays vs. Retina displays). Modern browsers and operating systems often use techniques like device pixel ratio (DPR) to ensure that CSS pixels render consistently on high-resolution displays.

Use Cases of PX:

  1. Precise Element Sizing: PX is ideal when you need exact dimensions for elements like buttons, icons, or images, where having fixed sizes is important for maintaining the design’s integrity.
    • Example: Setting a button’s width and height to 100px by 40px guarantees that the button will always be exactly that size, regardless of the device or browser.
  2. Design Consistency: When creating pixel-perfect layouts where the designer requires precise and consistent sizing across different browsers, PX ensures that all elements render exactly as specified.
    • Example: For logos, icons, or fixed headers and footers, where exact size and alignment are critical, PX ensures they appear as intended across different devices.
  3. Avoiding Scaling Issues: In some cases, using relative units like EM or REM might cause unintended scaling effects, especially in nested elements. PX can be used to avoid this issue by ensuring that elements remain fixed in size.
    • Example: When designing small interface elements like toolbars, status bars, or tiny UI components where scaling is undesirable, PX ensures the elements maintain their intended size.
  4. When Responsiveness Isn’t Critical: PX is useful for components that do not need to scale or adapt to different screen sizes or resolutions, such as fixed-width sidebars, pixel-perfect graphics, or print-like layouts.
    • Example: In some fixed-width websites or specific sections where responsive design is not necessary, PX allows for precise control without worrying about how the design will scale.

When to Avoid PX:

  1. Responsive Design: Since PX is an absolute unit, it doesn’t scale naturally with screen size or user preferences. For responsive design, using relative units like REM or percentages is generally better because they adjust based on the user’s device and settings.
  2. Accessibility: PX can limit accessibility since users who increase or decrease their browser’s default font size may not see changes in elements sized with PX. This can lead to issues with text readability or layout usability for users with visual impairments.
  3. Fluid Layouts: In modern web design, fluid and flexible layouts are more common, and PX can be rigid in comparison. For websites that need to adapt to various screen sizes and resolutions, relative units like REM or EM offer more flexibility.

Example of PX in CSS:

body {
font-size: 16px;
}

h1 {
font-size: 32px; /* Always 32px regardless of parent or screen size */
}

button {
width: 120px;
height: 40px;
padding: 10px;
}

Summary:

  • Advantages:
    • Provides exact control over element sizing.
    • Ideal for fixed-size elements like icons, logos, and buttons.
    • Useful in designs that require pixel-perfect accuracy.
  • Disadvantages:
    • Not responsive: Does not adjust automatically based on screen size or device.
    • Accessibility limitations: Does not scale with user settings or browser preferences.
    • Can lead to rigid designs that don’t adapt well to different environments.

In modern web development, while PX is still useful for certain fixed-size elements, it’s often used in combination with relative units like REM and EM to ensure both precision and responsiveness.

What are MM in CSS?

In CSS, MM (millimeters) is a physical unit of measurement that represents real-world millimeters. It is part of a set of absolute units designed to reflect physical dimensions (like inches, centimeters, and points). While PX, REM, and EM are more commonly used in web design, MM can be used in certain cases where physical dimensions matter, such as for print styling.

Characteristics of MM:

  1. Absolute Physical Unit: MM is an absolute unit that corresponds to a real-world millimeter. The CSS specification maps 1mm to a millimeter on paper or a screen, though screen resolutions and DPI (dots per inch) can affect the accuracy of this mapping.
  2. Device-Dependent: On screens, the exact size of 1mm may vary depending on the device’s resolution and DPI settings. While the browser attempts to match the MM unit to physical dimensions, this can be imprecise on various displays due to different screen densities and scaling settings.
  3. Commonly Used for Print: MM, along with other physical units like centimeters (cm), inches (in), and points (pt), is most often used in print-specific CSS (@media print), where exact real-world dimensions are needed. These units are helpful when designing print layouts, such as invoices, brochures, or other printed materials where you want precise control over the physical size of elements.

Use Cases of MM:

  1. Print Media: MM is useful when creating CSS for print media, where you need elements to have specific physical dimensions on paper.
    • Example: If you are styling a printable document or report that requires certain elements (such as margins, images, or text) to have specific sizes in millimeters, you can use MM to set these dimensions precisely.
  2. Precision for Real-World Objects: If your design involves objects that must correspond to real-world measurements, such as printing designs for business cards, labels, or forms, MM provides an exact, measurable unit.
    • Example: A business card with specific dimensions, such as 85mm by 55mm, can be accurately styled using the MM unit to reflect its real-world size.
  3. Designing for High-Precision Outputs: In some cases, you may design for high-resolution or specialized displays where physical measurements matter, such as kiosks or large-format screens. However, MM is less commonly used in such cases because of the variability in screen size and resolution.

Example of MM in CSS:

@media print {
body {
margin: 10mm;
}

.business-card {
width: 85mm;
height: 55mm;
padding: 5mm;
}
}

Why MM Isn’t Commonly Used on Screens:

  • Imprecision on Screens: Since screen resolutions vary, and devices have different pixel densities (DPI), the browser’s attempt to map 1mm to an actual physical millimeter can be inaccurate. This makes MM less practical for web layouts or screen-based designs.
  • Better Options for Screen Design: For screen-based designs, units like PX, REM, EM, and percentages are more practical because they allow for responsive and flexible layouts that adjust based on the display’s characteristics, user preferences, and device.

PX vs MM

AspectPX (Pixels)MM (Millimeters)
DefinitionPX represents individual pixels on a screen, a unit of measurement used in digital design.MM is a physical unit of measurement (millimeters), often used for print design.
Usage ContextPrimarily used in digital/web design for screen-based layouts and elements.Used in print design or any medium where physical dimensions matter.
Measurement BasisRelative to screen resolution and the number of pixels per inch (PPI or DPI).An absolute unit based on the metric system, not influenced by screen resolution.
ScalabilityPixel dimensions do not scale across devices with different resolutions (unless using responsive units or scaling techniques).Millimeter measurements are fixed and do not change, ensuring accurate sizing in physical prints.
ConsistencyConsistency may vary depending on screen resolution (e.g., different results on a 72 DPI screen vs. a 300 DPI screen).Provides consistent, accurate physical dimensions, independent of screen or device.
ResponsivenessPX units need to be adjusted or scaled for responsiveness in digital designs.MM units are fixed and non-responsive, unsuitable for scalable digital design.
PrecisionOffers more precision for screen-based layouts, especially for pixel-perfect designs.Ideal for exact physical sizing, especially in print design, but lacks flexibility for digital media.
Common ApplicationsWeb design, mobile design, and any screen-based layouts where pixel-level control is needed.Print design (posters, brochures, business cards) or digital mockups where physical size is a concern.
ConversionNot directly convertible to physical units, as it depends on the device’s DPI/PPI.Directly corresponds to physical measurements, with 1mm being a standard size.
Scaling BehaviorAffected by the resolution and screen size; the same pixel value may appear differently on different screens.Remains constant, making it ideal for situations requiring precise physical dimensions.
Examplewidth: 200px; /* 200 pixels on screen, varies with screen DPI */width: 50mm; /* Always 50 millimeters in print */
Best Used ForDigital designs where control over pixel-perfect elements is crucial, and adjustments can be made for different screens.Print designs where accurate physical measurements are required, ensuring a consistent output.

Use Cases of PX and MM

Use Cases of PX (Pixels):

PX (pixels) is an absolute unit commonly used in web design for precise control over element sizing. Here are the main use cases for PX:

  1. Precise Control Over Element Sizes: PX is ideal when you need exact, fixed sizes for elements like buttons, icons, and images. This ensures that these elements maintain their exact dimensions regardless of screen size, resolution, or context.
    • Example: A button with a width of 150px will always be 150 pixels wide, maintaining consistent design across different platforms and devices.
  2. Pixel-Perfect Layouts: When designers aim for pixel-perfect accuracy, particularly when designing based on mockups or prototypes, PX ensures that the design elements match the exact sizes specified in the design.
    • Example: A logo that needs to remain exactly 50px in height to match the brand’s design guidelines.
  3. Consistency in Fixed Layouts: For fixed-width layouts (as opposed to fluid or responsive layouts), PX ensures that elements are of a fixed size, making it easier to maintain consistency across different sections of the site.
    • Example: A fixed sidebar of 300px width that stays the same size regardless of the viewport or browser width.
  4. Small Interface Elements: When designing UI components like icons, tooltips, or dropdown menus, which need to maintain exact sizes, PX ensures precise control, especially for small elements.
    • Example: An icon set where each icon is 24px by 24px to maintain visual consistency.
  5. Where Responsiveness Isn’t a Priority: If a website or application is built to have fixed dimensions and responsiveness isn’t necessary, PX provides the precise measurements needed for rigid layouts.
    • Example: Certain enterprise software interfaces or dashboards, where elements need to remain fixed for functional reasons.
  6. Consistent Spacing: PX can also be used for spacing elements consistently, such as margins, padding, or gaps between elements, when precise control is important.
    • Example: Consistently defining 20px of padding around elements in a card layout.

Use Cases of MM (Millimeters):

MM (millimeters) is a physical unit of measurement in CSS, mainly useful for print-related design or physical dimensions. Here are the use cases for MM:

  1. Print-Specific Layouts: MM is ideal when designing for print, where exact real-world dimensions are needed, such as business cards, brochures, invoices, or other printed materials.
    • Example: Designing a business card with exact dimensions of 85mm by 55mm to match the physical specifications for printing.
  2. Real-World Sizing: If a design must match exact physical measurements in the real world (e.g., labels, packaging, or printed forms), MM ensures precise control over the dimensions.
    • Example: Creating printable forms that must fit within a certain real-world size (e.g., a label of 40mm by 30mm).
  3. Designing for Physical Media: MM is useful for physical media design where items need to be accurately sized, such as posters, flyers, or custom print designs.
    • Example: A poster design where margins or elements need to be positioned a specific number of millimeters from the edge of the paper.
  4. Exact Measurement for High-Precision Outputs: For designs that need precise physical measurements for high-quality printing or fabrication (such as technical drawings, blueprints, or product labels), MM provides the required level of precision.
    • Example: Designing a technical drawing or a packaging prototype with exact measurements in millimeters.
  5. Physical Object Prototyping: MM can be used for web-based interfaces that allow users to design or customize physical objects, where the final output must have specific dimensions.
    • Example: An online tool for customizing product packaging, where the user specifies dimensions in millimeters, and the output must match those dimensions when printed.
  6. Use in Combination with Print Media Queries: When creating styles specific to print media using @media print, MM can ensure that layouts translate properly to physical printouts, with precise margins, padding, and other dimensional properties.
    • Example: Setting margins for a printable invoice to exactly 15mm using CSS print styles.

Comparison of Use Cases:

  • PX is best for digital designs where exact pixel sizes are important, particularly in non-responsive layouts, small interface elements, and situations where fixed size and precision are essential.
  • MM is best for print and real-world physical layouts, where exact physical dimensions are required, ensuring that the design translates accurately to paper or physical materials.

FAQ on PX to MM

How does the PX to MM converter work?

The PX to MM converter uses a specific algorithm to transform pixel values into millimeters. It considers the DPI (dots per inch) of your screen or image. By inputting your pixel measurement and the DPI, it accurately converts it to millimeters for precise results in design and web applications.

Why would I need to convert pixels to millimeters?

Converting pixels to millimeters is crucial for digital and print design. It helps achieve accurate layout dimensions, ensuring that what you see on-screen matches the physical print size. This is especially useful when working with print resolution, web design, and interface dimensions to maintain consistency across different mediums.

What is the formula for converting PX to MM?

The general formula involves dividing your pixel value by the DPI (dots per inch) and then multiplying by 25.4 (since an inch equals 25.4 millimeters). This converts the pixel measurement into millimeters, essential for detailed CSS units and precise web design layouts.

Can I use the PX to MM converter for printing?

Absolutely. The PX to MM converter is beneficial for printing. By converting pixels to millimeters, designers can ensure that digital images and graphic resolutions translate accurately in print, maintaining the intended size and quality. This is critical for print design and image optimization.

How accurate is the PX to MM conversion?

The conversion accuracy depends on the correct input of DPI. Accurate DPI values yield precise millimeter measurements. Always verify the DPI settings of your digital image or screen for the best results, ensuring your designs translate accurately across digital and print media.

What is DPI, and why does it matter in converting PX to MM?

DPI stands for dots per inch. It measures the resolution of a digital image or screen. Higher DPI means more detail. When converting pixels to millimeters, DPI determines the scale and quality of the conversion. Accurate DPI input is crucial for correct measurement and layout design.

Are there any tools that can help with PX to MM conversion?

Yes, several online tools and graphic design software offer PX to MM conversion features. These tools often include additional functions like image editors, layout design aids, and digital measurement utilities to streamline the design process, making accurate conversions quick and straightforward.

Does screen size affect the PX to MM conversion?

Screen size itself doesn’t directly affect the conversion, but the screen’s DPI does. Different devices have varying DPI values, so using the correct DPI for your specific screen ensures accurate pixel to millimeter conversion, which is vital for web design and responsive design.

Can I convert pixels to other units like inches or centimeters?

Yes, pixels can be converted to other units like inches and centimeters using similar formulas. For inches, divide by DPI directly. For centimeters, first convert to inches, then multiply by 2.54. These conversions are essential for comprehensive layout and interface design.

How do I find the DPI of my screen or image?

Finding the DPI can typically be done in the settings of your graphic design software or the device’s display settings. Devices often list their DPI among screen specifications. Knowing the DPI is crucial for precise digital graphics, screen measurement, and ensuring accurate PX to MM conversions.

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