Pixels to rem and em.
Set a root size, paste a list of pixel values, and get rem and em in one table.
Unit conversion happens in the browser. Nothing is uploaded.
What it does
About the Px to Rem/Em Converter.
A px to rem converter divides pixel values by a root (or parent) font size so you can paste rem and em units that scale with the user’s settings.
Most browsers default to 16px root, but design systems often set 10px or 62.5% tricks. This tool lets you set that root, paste several pixel values, and read rem and em in one table.
How to use
Three steps.
Set
Set the root font size (and parent size if you need em).
Read
Paste one pixel value or a list of values.
Copy
Copy rem, em, or the whole table into your CSS or tokens.
When to use it
Where it helps.
Use it when a mock is in pixels but the codebase is rem-based, or when you are migrating a legacy stylesheet. Confirm the live html font-size before you trust the default 16.
FAQ
FAQ.
What is the difference between rem and em?
rem is relative to the root element (usually html). em is relative to the parent’s font-size. Nested em values compound; rem does not.
Why is 16px the default root?
User agents typically start at 16px. If your CSS sets html { font-size: 62.5% } or a pixel root, change the root field in this tool to match production.
How do I copy the converted units?
Copy an individual rem or em value, or copy from the table if you pasted a list. Paste into custom properties or utility maps.
Does this send my values anywhere?
No. Unit conversion is local arithmetic in the browser.