PX to REM Converter
Convert between pixel and rem units with custom base font size.
What is Pixel to REM Converter?
A PX to REM converter is an online tool specifically designed for web developers and UI designers who need to convert pixel (px) values to rem units for CSS styling. The rem unit (root em) is relative to the root HTML element's font size, which defaults to 16px in most browsers. This tool instantly calculates the correct rem value for any pixel input, making it easy to write scalable, accessible CSS without manual division.
Using rem units instead of fixed pixels is a best practice in modern web development because rem values scale with the user's browser font size preferences. When a user sets their browser to display larger text for accessibility reasons, rem-based layouts scale proportionally while pixel-based layouts remain fixed and can become hard to read. This makes rem units essential for building inclusive, accessible web interfaces that respect user preferences.
This converter is used daily by front-end developers translating Figma or Photoshop design mockups (which use pixels) into accessible CSS (which should use rem). It supports custom root font sizes for projects that set a different base size on the HTML element, such as 10px (which makes the math simpler: 1rem = 10px) or 14px for more compact designs. It also converts rem back to px for verification.
How to Use Pixel to REM Converter
- 1Step 1: Open the PX to REM Converter and verify or set the root font size — the default is 16px, which is the browser default, but you can change it to match your project.
- 2Step 2: Enter the pixel value from your design mockup or CSS file — for example, '24' for 24px text size, '48' for a 48px margin, or '320' for a 320px container width.
- 3Step 3: The tool instantly calculates and displays the equivalent rem value — for a 16px root, 24px becomes 1.5rem, 48px becomes 3rem, and 320px becomes 20rem.
- 4Step 4: Copy the rem value directly into your CSS stylesheet or design token file, replacing the hardcoded pixel value with the accessible rem equivalent.
- 5Step 5: Use the reverse conversion (rem to px) to verify existing rem values in your codebase or to understand what a specific rem value renders as at the default browser font size.
Benefits of Using Pixel to REM Converter
- ✓Accessibility Compliance: Converting px to rem is fundamental to building WCAG-compliant interfaces that respect browser font size settings for users with visual impairments.
- ✓Custom Base Font Size Support: Accommodates projects that set the HTML font size to 10px (for easy 1:10 math) or any other base, making the tool flexible for different team conventions.
- ✓Design-to-Code Workflow: Bridges the gap between pixel-based design tools (Figma, Sketch, Photoshop) and rem-based CSS, eliminating manual division from the developer workflow.
- ✓Bidirectional Conversion: Converts both px to rem and rem to px, making it useful both when writing new CSS and when auditing or debugging existing stylesheets.
- ✓Responsive Design Support: Encourages the use of relative units that work harmoniously with responsive layouts and fluid typography systems in modern CSS frameworks.
- ✓Speed and Accuracy: Instant results eliminate the repetitive mental math of dividing by 16 (or your base font size) for every value, reducing errors and speeding up development.
Example
About Pixel to REM Converter
Pixel to REM Converter helps web developers convert pixel values to rem, em, points, and centimeters based on a configurable root font size. Consistent use of relative units improves accessibility and responsive design. Adjust the base font size to match your project's root setting.
- Converts px to rem, em, pt, cm
- Configurable root font size
- Essential for responsive design
- Instant conversion as you type