px to em/rem Converter
Convert px to em/rem based on base font size. Supports bulk CSS conversion.
Single Conversion
1.5rem
em/rem = px value ÷ base font size
Bulk CSS Conversion
Input CSS
Output CSS
How to Use
1
Set Base Font Size
Browser default is 16px. Adjust according to your parent element's font-size.
2
Single or Bulk Conversion
Convert a single px value or paste entire CSS code for bulk conversion.
3
Copy Result
Copy the converted result and use it in your project.
What is px to em/rem Conversion
em and rem are relative size units. em is relative to the parent element's font-size, while rem is relative to the root element (html) font-size. They scale properly when users change browser font settings, making them ideal for accessible design.
Features
- Single ConversionInstantly calculate em/rem value from px input
- Bulk CSS ConversionPaste entire CSS code and convert all px values at once
- em/rem ToggleSwitch between em and rem output units
- Conversion OptionsFine-tune what to convert (skip 1px, borders, shadows)
Use Cases
- Accessible web coding
- Scalable typography design
- Component-based spacing systems
- Refactoring existing CSS to rem
- Unifying units in design systems
FAQ
What's the difference between em and rem?
em is calculated relative to the parent element's font-size. rem is always relative to the root element (html) font-size, providing consistent sizing regardless of nesting depth.
Why is 16px the default base font size?
Most browsers set the default font-size to 16px. Unless explicitly changed, 16px is the standard base for calculations.
When should I use rem vs vw?
rem follows user font settings, ideal for text and text-related spacing. vw follows viewport width, better for layouts and viewport-responsive elements.