Pixel (px) to Rem Converter
Use our pixel to rem converter to convert pixels to rem instantly for responsive CSS. Includes the pixel to rem formula, how to convert px to rem, and why rem is useful for scalable typography and spacing.
What is Pixel to Rem Conversion?
Px (pixels) are fixed CSS units, while rem is a relative unit based on the root font size (the html element).
If you want a layout that scales consistently across an entire site, converting pixels to rem helps because rem values are tied to the root font size rather than each element’s local font size.
This pixel to rem converter (pixel to rem converter online) lets you convert pixel to rem using a base root size (commonly 16px), which matches how most developers convert px to rem in CSS.
Pixel to Rem Formula
To convert pixels to rem, divide the pixel value by the root font size (in px).
rootPx is typically 16px by default, but it can be changed in CSS.
Use this when you know the rem value and want the pixel equivalent.
A common pixel to rem conversion when the root font size is 16px.
If you set html { font-size: 10px }, rem values scale from 10px.
How to Use the Pixel to Rem Converter
- 1
Enter your root font size (rootPx), in pixels (commonly 16).
- 2
Enter the pixel value (px) you want to convert.
- 3
The converter calculates rem = px ÷ rootPx.
- 4
Use the rem value in your CSS for scalable typography and spacing.
Frequently Asked Questions
Use the pixel to rem formula: rem = px ÷ rootPx (root font size in pixels).
rem = px ÷ rootPx, where rootPx is usually 16px by default.
Many browsers default to 16px, but you should use whatever root font size your CSS sets on the html element.
It helps create consistent, scalable designs. rem is based on the root font size, so spacing and typography scale together.
Yes—this tool converts px to rem instantly based on your chosen root font size.
No. rem is based on the root (html) font size, while em is relative to the current element’s font size (or parent, depending on the property).