Ready to make your website’s design truly responsive? Our free PX to REM Converter is the perfect little tool to help you stop guessing and start scaling. It easily translates fixed pixel (PX) values into flexible, accessible REM units, taking the manual math off your plate. This is the secret to making layouts and text that look great on any screen.
Best PX to REM Converter Online
Our PX to REM Converter is an essential utility for any modern web developer or designer looking to build more flexible and accessible websites. It provides a simple, instant, and accurate way to translate static pixel-based designs into fluid, scalable REM units. By doing the simple calculation for you ( PX value / Base Font Size = REM value ), this tool saves you time and removes the guesswork from your workflow. This allows you to focus less on mental math and more on creating beautiful layouts that adapt perfectly to every user’s device and accessibility needs.
How to Use This Tool
- Check Your Base: First, confirm your project’s root font size. If you haven’t set it in your CSS, it’s almost certainly 16. Enter this value in the “Base Font Size (PX)” field.
- Enter Your Pixels: In the “PX” box, type the pixel value you want to convert (for example,
24for padding,600for a container width, etc.). - Get Your REM: The “REM” field will automatically display the correct REM equivalent (e.g.,
1.5for 24px). - Copy and Reset: You can use the “Copy REM” or “Copy PX” buttons to grab the values you need. When you’re ready to start over, just hit “Reset”.
Example
Let’s walk through a super common scenario.
Imagine you’re building a blog, and your design mockup (from Figma or Photoshop) says the main body text should be 18px and the article heading (<h1>) should be 40px.
Your website’s base font size is the browser default, 16px.
Here’s how you’d use the tool:
- Leave the “Base Font Size (PX)” at 16.
- Type 18 into the “PX” box.
- The “REM” box will instantly show 1.125.
- Next, you type 40 into the “PX” box.
- The “REM” box will update to 2.5.
Now you know exactly what to put in your CSS file:
CSS
p {
font-size: 1.125rem; /* This is 18px */
}
h1 {
font-size: 2.5rem; /* This is 40px */
}
Common PX to REM Conversions (Base: 16px)
| Pixels (px) | REM |
| 1px | 0.0625rem |
| 2px | 0.125rem |
| 4px | 0.25rem |
| 8px | 0.5rem |
| 10px | 0.625rem |
| 12px | 0.75rem |
| 14px | 0.875rem |
| 16px | 1rem |
| 18px | 1.125rem |
| 20px | 1.25rem |
| 24px | 1.5rem |
| 28px | 1.75rem |
| 32px | 2rem |
| 40px | 2.5rem |
| 48px | 3rem |
| 56px | 3.5rem |
| 64px | 4rem |
| 72px | 4.5rem |
| 80px | 5rem |
| 96px | 6rem |
| 128px | 8rem |
Use Cases
- Responsive Typography: The most common use! Convert your entire typographic scale (h1, h2, h3, p, etc.) from a static PX-based design mock-up into fluid REM units.
- Accessible Spacing: Don’t just stop at text. Use REM for
margin,padding, andgapto ensure your layout’s white space scales proportionally with the text. - Converting Legacy CSS: Have an old website built with pixels? You can use this tool to quickly update your old
pxvalues to modernremunits as part of a site redesign. - Learning and Education: It’s a fantastic hands-on way for new developers to visually understand the relationship between pixels and relative REM units.
- Media Query Management: While you might use PX or EM for media queries, you can use REMs for the content inside those queries to ensure it scales correctly within each breakpoint.
Frequently Asked Questions (FAQs)
Q: What’s the real difference between PX and REM?
Think of it this way: a PX (pixel) is a fixed, absolute unit. 16px is always 16px, no matter what. A REM (root em), on the other hand, is a relative unit. It gets its value from the font size of the website’s root element (the <html> tag). If the root font size is 16px, then 1rem equals 16px, 2rem equals 32px, and so on.
Q: Okay, but why is REM better for my site?
Accessibility! If a user with a visual impairment zooms in or increases their browser’s default font size, a website built with REM units will scale up perfectly—text, buttons, and spacing. A site built with only PX units might break, overlap, or become unreadable. REM makes your design flexible for everyone.
Q: What is this “Base Font Size” I need to enter?
The “Base Font Size” is simply the font size you (or your browser) have set for the <html> element. For 99% of browsers, the default is 16px. Our tool defaults to 16, but if your CSS file sets html { font-size: 14px; }, you would just change the base size to 14 to get accurate conversions.