EM to PX Converter

Use our EM to PX Converter for accurate CSS units conversion. Simplify your web design and ensure responsive, scalable typography.

EM to Pixels (PX)

We’re assuming the standard default browser font-size of 16px

EMPixels
0.01em0.16px
0.03em0.48px
0.05em0.8px
0.08em1.28px
0.1em1.6px
0.15em2.4px
0.2em3.2px
0.5em8px
1em16px
2em32px
3em48px
4em64px
5em80px
6em96px
8em128px
10em160px
15em240px
20em320px
30em480px
40em640px
50em800px
60em960px
80em1280px
100em1600px

Pixels (PX) to EM

PixelsEM
1px0.0625em
2px0.125em
3px0.1875em
4px0.25em
5px0.3125em
6px0.375em
8px0.5em
10px0.625em
12px0.75em
14px0.875em
15px0.9375em
16px1em
18px1.125em
20px1.25em
24px1.5em
25px1.5625em
28px1.75em
32px2em
36px2.25em
40px2.5em
44px2.75em
48px3em
50px3.125em
56px3.5em
64px4em
72px4.5em
75px4.6875em
80px5em
90px5.625em
100px6.25em

What is EM in CSS?

EM is a CSS unit of measurement that is relative to the font size of the current element or its parent element. Like REM, it is used to create flexible, scalable layouts, but with one key difference: while REM is relative to the root element’s font size, EM is relative to the font size of the element it’s applied to (or the nearest parent element).

Here’s how EM works:

EM: This unit is relative to the font size of the element or its parent element. For instance, if a parent element has a font size of 16px, then 1em equals 16px. However, if the font size of a parent or containing element changes, the EM values inside it adjust proportionally, which can sometimes result in compounding or cascading size effects.

Example:

  • If the parent element has a font size of 16px and you set a child element to 2em, the child element’s font size will be 32px (2 * 16px).
  • If the parent element has a font size of 16px, but you apply 2em to the parent and 2em to the child, the child’s font size will be 64px (because it multiplies by the parent’s new size).

Advantages of EM:

  • Relative to Parent: It provides flexibility in nested contexts where you want elements to scale based on the size of their parent element.
  • Versatile: It is often used for sizing elements like padding, margins, and font sizes where flexibility is needed.

Potential Downsides:

  • Cascading Effects: The size of elements can quickly become difficult to manage because they depend on their parent elements, leading to larger-than-expected values if the EM units are applied multiple times in a hierarchy.
  • Less Predictability: Compared to REM, which remains consistent across a page, EM units can change in unpredictable ways, especially in nested structures.

Difference Between EM and REM:

  • EM is relative to the font size of the parent element or the element itself.
  • REM is always relative to the root element’s font size, making it more predictable and easier to manage for larger projects, especially in responsive design.

In summary, while EM is great for situations where you want an element to scale with its parent, it requires more attention in complex layouts to avoid unintentional size increases.

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.

EM vs PX

AspectEMPX (Pixels)
DefinitionEM is a relative unit of measurement based on the font size of the parent element.PX represents a fixed, absolute number of pixels on the screen.
Usage ContextCommonly used for scalable and responsive layouts, where sizes need to adjust relative to the parent element.Used for fixed dimensions, providing precise control over layout, spacing, and font sizes.
Measurement BasisRelative to the font size of the parent element or its container.Fixed and absolute, relative to screen resolution (DPI/PPI), but does not scale inherently.
ScalabilityScales based on the parent’s font size, making it flexible for responsive design.Does not scale; maintains the same size across different devices unless manually adjusted with media queries or responsive techniques.
ConsistencyCan vary depending on the size of the parent element, leading to more fluid and flexible designs.Consistent across devices with the same resolution, but appears differently on high-DPI (retina) screens.
ResponsivenessEM is naturally responsive, adjusting based on the parent element’s size, making it ideal for dynamic, fluid layouts.PX units are not inherently responsive and require additional techniques like media queries to adapt to different screen sizes.
PrecisionProvides flexibility in scaling, but less precise when exact, fixed dimensions are needed.Offers pixel-perfect precision, making it ideal for fixed layouts where exact control is necessary.
Common ApplicationsSuitable for text scaling, padding, margins, and responsive typography where relative sizing is beneficial.Used in web design for fixed layouts, elements, and spacing that require precise, consistent measurements.
InheritanceInherits from the parent element’s font size, leading to potential compounding effects when nested.Does not inherit; maintains the exact pixel value assigned, regardless of the parent element.
ConversionRelative to the font size of the parent (e.g., 1em = 100% of the parent’s font size).1px is 1 pixel on the screen, with no conversion needed.
Scaling BehaviorScales automatically with changes in the parent element’s font size, useful for dynamic and fluid layouts.Does not scale unless manually adjusted, often appearing differently on different resolution screens.
Examplefont-size: 1.5em; /* 1.5 times the parent element's font size */font-size: 16px; /* Fixed at 16 pixels regardless of parent */
Best Used ForBest for creating scalable, flexible layouts that adapt to parent elements or screen sizes.Best for precise, pixel-perfect designs where fixed dimensions are critical, such as logos or specific elements.

Use Cases of EM and PX

Use Cases for EM:

EM units are useful when you want elements to scale based on the font size of their parent or themselves, making them ideal for nested components or when relative scaling within specific contexts is desired.

Component-Level Sizing:

  • If you have a reusable component and want its child elements to scale relative to the parent’s size, EM works well. This is often the case in UI elements like buttons, cards, or navigation menus where the sizing of child elements needs to adapt based on the parent component’s font size.

Example:

.button {
font-size: 1.5em; /* Scales relative to parent font size */
padding: 0.5em 1em;
}

Nested Layouts and Local Control:

  • In cases where you want nested elements to scale based on their immediate parent’s font size (not the root element), EM offers greater flexibility.
  • For example, in a navigation bar or card component, you might want buttons, labels, or icons to scale with the parent rather than the entire page.

Example:

.menu {
font-size: 1.2em; /* Sets the base font size for the menu */
}
.menu-item {
font-size: 1em; /* Inherits and scales based on .menu */
}

Fine-Tuning Localized Sizing:

  • EM allows for more granular control of the sizing within smaller or nested elements. For example, if you have a container with a specific font size, EM helps to ensure that padding, margins, or font sizes inside the container stay in proportion to it.

Example:

.box {
font-size: 1.2em;
padding: 1em; /* Padding will be proportional to the container's font size */
}

Typography in Nested Elements:

  • When working with nested typography, EM allows child elements to scale based on their direct parent. For instance, if you have a heading within a section of the page that should have a larger font size relative to the rest of the content, you can apply EM units.

Example:

.section {
font-size: 1.5em;
}
.section h2 {
font-size: 1.2em; /* Scales based on the section's font size */
}

Use Cases for PX (Pixels):

PX is one of the most commonly used CSS units for web design. It represents an absolute unit of measurement, where 1px is a fixed, non-scalable value. While PX units don’t scale with user preferences, they are reliable for maintaining precise control over design elements.

Pixel-Perfect Designs:

Use PX when you need precise control over the layout, ensuring that elements display exactly as intended on different devices. This is common for graphic-heavy designs, buttons, and icons where specific sizing is critical.

Example:

.icon {
width: 32px;
height: 32px;
}

Fixed-Width Layouts:

When creating fixed-width layouts (e.g., landing pages or banners) that need to maintain exact dimensions regardless of screen size or resolution, PX is often preferred. It ensures that elements remain the same size across different devices.

Example:

.container {
width: 960px;
}

Fonts with Fixed Sizes:

PX is often used for font sizes in specific elements where precise control is required, such as in logos, headings, or UI components where the font needs to remain consistent across different devices and browsers. However, PX can hinder accessibility if used too broadly in typography, as it doesn’t adapt to user settings.

Example:

h1 {
font-size: 36px;
}

Raster Images and Icon Sizing:

When dealing with raster images (PNG, JPG) or pixel-based icons, PX is ideal because images are based on pixels, and sizing them in PX ensures no distortion or scaling that could compromise image quality.

Example:

img {
width: 300px;
height: auto;
}

User Interface (UI) Components:

In UI design, many UI components (e.g., buttons, toolbars, form elements) are designed using PX values to ensure consistency across different browsers and screen resolutions, especially when maintaining pixel-perfect rendering is crucial.

Example:

.button {
padding: 10px 20px;
}

Legacy or Non-Responsive Designs:

Older websites or designs that aren’t responsive often use PX because it’s simple to implement and ensures consistent dimensions. Although this approach is not ideal for modern responsive designs, it can still be useful in controlled environments.

FAQ on EM to PX

What is an EM and how does it relate to PX?

EM is a relative unit used in CSS that is based on the font-size of the element. One EM equals the current font size. If the font size is 16px, then 1EM = 16px. It’s a flexible unit, perfect for scalable designs in web development.

How do I convert EM to PX manually?

To convert EM to PX, multiply the number of EM units by the base font size (in PX). For example, if 1EM = 16px and you have 2EMs, then it’s 2 16 = 32px. This calculation helps in making precise adjustments in *responsive web development.

Why should I use EM instead of PX?

Using EM units offers flexibility in typography settings. It allows your design to scale according to the user’s preferences and browser settings. This ensures better user experience and accessibility. It’s essential for making responsive and scalable layouts—key aspects of modern web design.

Is there any difference between EM and REM?

Yes, there’s a significant difference. EM is relative to the parent element’s font size, while REM stands for “Root EM,” and it’s relative to the root element (typically the HTML element). This distinction helps in creating consistent and predictable layouts in CSS styling.

Can you convert REM to PX?

Indeed, you can convert REM to PX. Similar to EM to PX conversion, multiply the REM value by the root element’s font size. For instance, if the root font size is 16px and you have 1.5REM, it converts to 1.5 16 = 24px. This helps in maintaining design *consistency.

What are the common use cases for EM units?

EM units shine in responsive typography and dynamic sizing for web components. They’re often used to set font sizes, paddings, and margins in a flexible way, adapting to different screen sizes and user settings, which is crucial for modern web design and development.

How does screen resolution affect EM to PX conversion?

Screen resolution, measured in PPI (Pixels Per Inch), doesn’t directly affect the EM to PX conversion because EM units are relative to the font size, not the screen’s resolution. However, understanding screen resolution is important for overall design consistency in responsive web development.

Can EM units be used for non-text elements?

Certainly! EM units can be used for margin, padding, width, and height in addition to text elements. This makes them versatile for creating scalable designs. Their adaptability ensures that all aspects of the layout remain proportionate, enhancing the responsive design experience.

What tools can help with converting EM to PX?

There are plenty of online tools like CSS Size Unit Converters, as well as browser extensions and web development tools. These tools save time and provide accurate conversions, helping to maintain design accuracy and enhance workflow in web development.

Are there any pitfalls to watch out for when using EM units?

One common issue is the cascading nature of EM units, which can lead to unexpected scaling if not managed carefully. Always be mindful of parent elements’ font sizes to avoid unexpected results. Consistent review and testing are key in mitigating these challenges in web design.

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