EM to PX Converter

Convert element-relative EM units to absolute pixel values

EM to PX Calculator

About EM to Pixel Conversion:

EM units are relative to the font size of their parent element. To convert EM to pixels, multiply the EM value by the parent element's font size in pixels.

px
Default browser font size is 16px
em
The EM value you want to convert
Conversion Result
16px
1em = 16px
Parent: 16px

Font Size Preview

See how this EM value looks as font size:

The quick brown fox jumps over the lazy dog.

Text displayed at 0 using a parent font size of 16px.

EM Inheritance Visualization

Demonstrates how EM values compound when nested:

Parent (16px)

Text @ 1em = 16px

Text @ 1em = 16px

Parent (16px)

Text @ 1.5em = 24px

Text @ 1.5em = 36px

Batch Converter

Convert multiple EM values at once. Enter values separated by spaces, commas, or new lines.

Batch Results
EM Pixels CSS Code

Common EM to PX Conversions

Based on the standard 16px parent font size, here are common conversions:

EM Pixels Common Use Case
0.25em 4px Small borders, minor spacing
0.5em 8px Standard spacing, small margins/padding
0.75em 12px Small text, labels, captions
1em 16px Base font size, standard spacing
1.25em 20px Large text, subheadings
1.5em 24px H3 headings, medium spacing
2em 32px H2 headings, large spacing
2.5em 40px Large headings, section spacing
3em 48px H1 headings, major spacing

Frequently Asked Questions

The main difference between EM and REM units lies in what they're relative to:

  • EM units are relative to the font size of their direct parent element. If the parent element's font size changes, all EM-based measurements in child elements will scale proportionally.
  • REM (Root EM) units are always relative to the root element's font size (the html element), regardless of parent element sizes.

Key differences in behavior:

  • EM units can create a compounding effect in nested elements, as each level inherits and multiplies the parent's size.
  • REM units provide more predictable sizing since they always reference the same base value.
  • EM units are useful for element-specific scaling, while REM units are better for global, consistent scaling.

A common practice is to use REM units for font sizes and margins/padding to maintain consistency, and EM units for component-internal measurements that should scale with their container.

EM units are particularly useful in these scenarios:

  1. Component-Based Design - When you want elements to scale relative to their parent component rather than the entire document. This creates self-contained, reusable components where all internal spacing maintains proper proportions.
  2. Typography Hierarchy - For creating consistent typography scales within components, where headings and text maintain proportional relationships.
  3. Component Internal Spacing - For padding, margins, and sizes within components that should scale with the component's own font size.
  4. Buttons and Input Elements - Where padding and sizing should scale proportionally with the text size.
  5. Media Queries - EM units can be useful in media query breakpoints for font-size relative design changes.

Advantages over other units:

  • vs. Pixels: EM units scale when the parent font size changes, while pixels remain fixed.
  • vs. REM: EM units create component-specific scaling, while REM units scale globally based only on the root font size.

Many modern design systems use a combination of units: REM for global sizing and document-level spacing, and EM for component-internal measurements.

To calculate pixel values from EM units manually, use this formula:

Pixels = EM Value x Parent Element's Font Size in Pixels

For example, if your parent element's font size is 16px:

  • 1em = 1 x 16px = 16px
  • 1.5em = 1.5 x 16px = 24px
  • 2em = 2 x 16px = 32px
  • 0.75em = 0.75 x 16px = 12px
  • 0.5em = 0.5 x 16px = 8px

If the parent element has a font size of 20px:

  • 1em = 1 x 20px = 20px
  • 1.5em = 1.5 x 20px = 30px
  • 2em = 2 x 20px = 40px

For nested elements using EM, you need to account for the compounding effect:

/* Starting with 16px base */ body { font-size: 16px; } .parent { font-size: 1.5em; } /* 1.5 x 16px = 24px */ .parent .child { font-size: 1.5em; } /* 1.5 x 24px = 36px */

There are several strategies to manage the EM compounding effect in nested elements:

  1. Use REM instead of EM for font sizes to avoid compounding entirely. REM always references the root font size.
    font-size: 1.5rem; /* Always relative to root */
  2. Reset font sizes at container levels using specific pixel or REM values to create a new baseline.
    .container { font-size: 16px; /* Reset baseline */ }
  3. Calculate the inverse to counteract the parent's scaling.
    .parent { font-size: 1.5em; } /* 24px */ .child { font-size: 0.667em; } /* 16px (0.667 x 24px) */
  4. Use a CSS preprocessor to calculate precise values based on your intended pixel sizes.
    @function em($pixels, $context: 16) { @return #{$pixels / $context}em; }

The EM compounding behavior isn't always undesirable. In some components, you might want internal elements to scale proportionally to create a coherent visual hierarchy.

About EM Units

EM units are a relative CSS measurement originally based on the width of the capital letter "M" in typography. In modern CSS, 1em equals the computed font size of the element on which it's used.

Key Points About EM
  • Context-Relative: Sized relative to parent element
  • Component Scaling: Creates self-contained, proportional components
  • Inheritance: Values compound in nested elements
  • Flexibility: Great for component-specific proportional scaling

EM units are particularly useful for creating component libraries and design systems where components need to scale consistently regardless of where they're used.

CSS Usage Examples

Common ways EM units are used in CSS:

/* Component with em-based internal spacing */
.card {
  font-size: 16px; /* Base size */
  padding: 1.25em; /* 20px */
  border-radius: 0.5em; /* 8px */
}

.card-title {
  font-size: 1.5em; /* 24px */
  margin-bottom: 0.5em; /* 12px */
}

.card-text {
  font-size: 1em; /* 16px */
  line-height: 1.5; /* 24px */
  margin-bottom: 1em; /* 16px */
}

.card-footer {
  padding: 0.75em 1em; /* 12px 16px */
  font-size: 0.875em; /* 14px */
}

/* Button with proportional padding */
.button {
  font-size: 1em; /* Inherits from parent */
  padding: 0.5em 1em; /* Scales with font size */
  border-radius: 0.25em; /* Scales with font size */
}

/* Different sized buttons using em */
.button-lg {
  font-size: 1.25em; /* 25% larger */
}

.button-sm {
  font-size: 0.8em; /* 20% smaller */
}

A common pattern is to use pixels or REM for container sizing, and EM for internal spacing of components to create consistent proportions.

Related Converters

PX to EM Converter EM to REM Converter REM to EM Converter REM to PX Converter All CSS Unit Converters