Bidirectional PX to REM & REM to PX Converter
Convert pixels to rem and rem to pixels instantly with custom root font size (16px / 10px) and standard Tailwind reference table.
About This Tool
PX to REM Converter helps developers convert pixel values into relative REM units for accessible, scalable web layouts, featuring customizable root font sizes and a full Tailwind CSS conversion reference table.
Key Features
Real-time bidirectional conversion (PX <-> REM)
Customizable root base font size (16px, 10px, or custom)
Interactive Tailwind CSS size reference table
One-click values loading
How to Use This Tool
- Enter a pixel value or a rem value in either input box.
- Choose your root font size (default 16px, or 10px 62.5% trick).
- Conversion updates bidirectionally in real time.
- Click any item in the reference table to load standard sizes.
Why Use This Tool
- REM units respect user browser font size preferences for accessibility.
- Bidirectional: calculate px from rem or rem from px instantly.
- Includes complete conversion reference table matching Tailwind CSS spacing scales.
Pro Tips
- Use REM for font sizes, margins, and padding, and PX for 1px borders
- Standard browser default root font size is 16px (1rem = 16px)
Frequently Asked Questions
Why should I use REM instead of PX in CSS?
REM units scale proportionally when users change their default browser font size, improving web accessibility.
What is the 62.5% CSS font-size trick?
Setting 'html { font-size: 62.5%; }' makes 1rem equal to exactly 10px (e.g. 1.6rem = 16px), simplifying mental math.