Converters
PX to EM Converter
Convert absolute pixel values to EM units for scalable and accessible CSS.
Default browser font size is 16px
The PX to EM converter is a tool that helps web developers and designers convert pixel values to EM units for CSS styling. This conversion is particularly useful for creating responsive designs and maintaining proper scaling across different screen sizes and devices.
What are Pixel Units?
Pixels (px) are fixed-size units that are used in screen media. One pixel is equal to one dot on the computer screen. Pixels are absolute units, which means they remain the same size regardless of parent element dimensions.
What are EM Units?
EM is a relative unit in CSS that is based on the font-size of the parent element. 1em equals the font-size of the parent element. If the parent element has a font-size of 16px (browser default), then 1em = 16px.
Conversion Formula
The conversion between pixels and EM is straightforward:
For example, with the default base font size of 16px:
- 16px = 1em (16 ÷ 16)
- 24px = 1.5em (24 ÷ 16)
- 32px = 2em (32 ÷ 16)
- 8px = 0.5em (8 ÷ 16)
Common PX to EM Conversions
| Pixel Value | EM Value (16px base) | Common Use |
|---|---|---|
| 8px | 0.5em | Very small text |
| 12px | 0.75em | Small text |
| 16px | 1em | Normal text (base size) |
| 20px | 1.25em | Slightly larger text |
| 24px | 1.5em | Subheadings |
| 32px | 2em | Headings |
| 48px | 3em | Large headings |
Advantages of Using EM Units
Converting from pixels to EM units offers several advantages:
- Scalability: EM units scale with the parent element's font size, making it easier to maintain proportions throughout your design.
- Accessibility: When users change their browser's default font size, EM-based layouts will scale accordingly, improving accessibility.
- Responsive Design: EM units make it easier to create designs that adapt to different screen sizes and device capabilities.
- Maintainability: Using relative units like EM makes it easier to update your design by changing just a few base values.
When to Use PX vs EM
While EM units are generally preferred for responsive design, there are cases where pixels might be more appropriate:
- Pixels: Better for elements that should never scale, like borders, shadows, and other decorative elements. Also useful when you need pixel-perfect precision.
- EM: Better for font sizes, padding, margins, and other elements that should scale with text size. Particularly useful for maintaining proportions in nested elements.
Browser Support
Both pixel and EM units are supported in all modern browsers and have been for many years. There are no compatibility concerns when using these units.