PX to REM Converter
Convert pixel (px) values to rem units instantly for scalable, accessible web design
I still remember the “aha!” moment when I realized why modern web design loves rem units. If you are a designer, developer, or just want your site to work for everyone, you have to move beyond fixed px values. That is why I built this PX to REM Converter so you can bridge the gap between old-school pixels and modern, responsive sizing in one click.
No more head math or guessing. Just pop in your pixel value and base font size, and this tool tells you the perfect rem value for your CSS.
What Are PX and REM in CSS?
PX stands for pixels – tiny squares on your screen. Using pixels is direct and easy, but it is not always flexible. If your user has a big screen, a small one, or changes their browser’s default size, px stays the same.
REM stands for “root em.” One rem equals the font size set on your page’s root element, which is usually 16 pixels by default. If a user or designer changes this, everything sized with rem units scales up or down automatically. That makes your design accessible, consistent, and a lot friendlier to everyone.
Why Convert PX to REM?
Here is why you want to convert px to rem:
- You want your site or app to work at every screen size and zoom level
- You are working with a design spec in pixels but coding in rem for accessibility
- You want to let users control font size without breaking your design
- Your team or framework uses rem, but your reference files use px
- You are building accessible, modern sites that meet the latest standards
This tool makes the process painless and helps you future-proof your styles.
What This Tool Does
Paste in your pixel value, set the base font size (or use the default 16), click convert, and instantly get the rem value. It works for decimals, big numbers, and fractional pixels. All calculations are done instantly and safely, right in your browser.
Input and Output Examples
Here are a few real-life cases:
Example 1:
Pixel value:
24
Base font size:
16
Output:
1.5 rem
Example 2:
Pixel value:
18
Base font size:
18
Output:
1 rem
Example 3:
Pixel value:
36
Base font size:
20
Output:
1.8 rem
This tool works for any value and gives you a clean, ready-to-copy answer.
How to Use This Tool (Step-by-Step)
- Enter your pixel value in the Pixel (PX) Value box.
- Enter the base font size (usually 16) in the Base Font Size box.
- Click Convert PX to REM.
- Copy the rem value from the output box.
- Use the value in your CSS or share it with your team.
- Click Clear All to start over.
You get instant results, with no downloads, and nothing sent anywhere.
What to Expect
You get a big, clear interface, fast conversion, and a tool that works everywhere – desktop, tablet, or mobile. All data is private, no values are stored, and you never have to fight with the interface.
Real-World Use Cases
- Designers use this tool to upgrade old px-based styles to scalable rem units.
- Developers convert spacing, padding, or text sizes for better accessibility.
- Teams with remote clients use it to translate specs and wireframes to modern code.
- Students use it to learn CSS the right way from day one.
Why PX to REM Conversion Matters
Modern web design needs to be flexible and accessible. Using rem units means your layouts and text always scale nicely, no matter the user’s device or settings. Pixel-perfect is great, but rem-perfect means everyone gets the best experience. This converter makes the switch easy.
Frequently Asked Questions (FAQs)
What does this tool do?
This tool converts pixel values to rem units, using any base font size.
What is the default base font size?
Most browsers use 16 pixels by default for the root font size.
Can I use decimal values for px?
Yes. The tool works for decimals and fractions.
Is the output always accurate?
Yes. The calculation is always px divided by base font size.
Can I change the base font size?
Yes. Enter any value you use on your site or app.
Does this tool store my values?
No. All calculations happen in your browser, with nothing stored or shared.
Does it work on all devices?
Yes. The converter is mobile-friendly and works everywhere.
Can I convert rem back to px?
Yes. For that, use our rem to px converter.
Why is rem better than px?
Rem units scale with user settings, so your site is more accessible and user-friendly.
Is this tool free to use?
Yes. Use it as often as you want, for free.