Pixel to EM Converter – Convert PX to EM for Responsive Design
About the Pixel to EM Converter
The Pixel to EM Converter converts values between pixels (px) and em units in either direction, using a customizable base font size (16px by default, matching most browsers). Enter a value, pick your conversion direction, and get an instant, precise result formatted to four decimal places for accurate CSS use.
It’s built for front-end developers and designers building responsive layouts where relative units like em scale better across different font sizes than fixed pixel values. Once you’ve converted your typography units, the CSS Border Radius Generator and CSS Text Shadow Generator are useful for building out the rest of your component’s styling.
The BigToolSite Team tested both conversion directions across a range of base font sizes, including non-default values like 62.5% (10px), to confirm the calculations stay accurate for common responsive design setups.
How to Use the Pixel to EM Converter
- Set your Base Font Size in pixels (defaults to 16px, the standard browser default).
- Enter the Value to Convert.
- Choose Convert PX to EM or Convert EM to PX.
- Click Convert to see your precise result.
- Use Copy Result to grab the converted value, or Clear to start over.
Example Usage
Input: Base Font Size: 16px, Value: 24px, Direction: PX to EM
Output: 1.5000 em
Input: Base Font Size: 16px, Value: 2em, Direction: EM to PX
Output: 32.00 px
Frequently Asked Questions
Most browsers use 16px as the default root font size, so 1em equals 16px unless your site’s CSS changes the root font-size property.
Em units scale relative to the font size of their parent element (or the root element for rem), which makes layouts more accessible and responsive to a user’s browser font size settings, unlike fixed pixel values.
Set the Base Font Size field to 10px (since 62.5% of the default 16px browser size is 10px), and the tool will calculate em values based on that adjusted base.
Em is relative to the font size of its immediate parent element, while rem is always relative to the root (html) element’s font size, making rem more predictable in deeply nested layouts.
Yes, it’s completely free with no signup required.
