REM to PX Converter
Convert rem units to pixels (px) for precise CSS measurements with configurable base font size
Base Font Size
Default browser size is 16px
Converter
Common Values (at 16px base)
Conversion Formula
Recommended Settings
Understanding REM Units
- •REM units are relative to the root (html) font size, not parent elements
- •1rem equals the base font size (typically 16px in browsers)
- •REM provides consistent, predictable scaling across your entire site
- •Converting to pixels helps understand exact spacing and sizing
When to Convert REM to PX
- •Debugging CSS layouts to understand exact pixel measurements
- •Converting design tokens from rem-based systems to pixel specs
- •Calculating spacing for integration with pixel-based frameworks
- •Understanding how rem values translate to actual screen dimensions
Most Popular
Most developers use 16px base font size matching browser defaults
When to Use This Tool
Convert rem units to pixels to understand exact measurements when debugging layout issues. This helps you verify spacing, sizing, and alignment matches design specifications when working with rem-based CSS frameworks or design systems.
Translate rem-based design tokens to pixel values for design handoff to teams using pixel-based tools. Designers often work in pixels while developers implement in rem, requiring accurate conversion for specification documentation.
Calculate pixel equivalents when integrating rem-based component libraries with pixel-based UI frameworks or legacy code. Understanding both units helps ensure consistent spacing across different parts of your application.
Determine how rem values render as pixels across different browser font size settings. Test accessibility by seeing how your rem-based layouts translate to pixels when users adjust their default font size preferences.
How It Works
Set the base font size (default is 16px, matching browser defaults)
Enter a value in rem (or px if using reverse mode)
The tool automatically calculates and displays the equivalent px (or rem) value
Adjust decimal precision (2-4 places) for rem accuracy in reverse mode
Click common values for quick conversions of standard rem sizes
Copy the converted value for use in your CSS or documentation
Use swap direction to convert from px to rem instead
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Browser Default Standards for optimal performance on modern browsers.
Secure
No data collection, no tracking, no sign-up required.
Frequently Asked Questions
Why convert REM to PX?
Converting REM to PX helps you understand exact pixel measurements when debugging layouts, documenting designs, or integrating with pixel-based systems. While rem is great for responsive design, sometimes you need to know the actual pixel values for precise control or troubleshooting.
Does the base font size affect all rem values?
Yes! All rem units are calculated relative to the root (html) font size. If you set the base to 16px, then 1rem = 16px, 2rem = 32px, etc. Changing the base font size affects all rem calculations proportionally, which is why rem is so powerful for responsive design.
What if users change their browser font size?
When users adjust their browser's default font size, all rem values scale accordingly while px values stay fixed. For example, if a user sets their browser to 20px instead of 16px, your 1rem becomes 20px instead of 16px. This is why rem is better for accessibility.
Should I use different base font sizes?
Generally, stick with 16px (the browser default) unless you have a specific design requirement. Changing the base font size can make your site feel inconsistent with other websites. If you need different sizes, use different rem values instead of changing the base.
Can I mix rem and px in my CSS?
Yes! It's common to use rem for typography and spacing (padding, margins) while using px for borders, shadows, and fine details. For example, use 'font-size: 1.5rem' but 'border: 1px solid'. This combines the flexibility of rem with the precision of px.
How does this work with responsive design?
REM units make responsive design easier because you can adjust the base font size at different breakpoints, automatically scaling all rem-based values. For example, set base to 14px on mobile and 16px on desktop to proportionally scale your entire layout.