px to rem Converter — CSS, Free | How to use and interpret results
Divide a pixel length by a supplied root font size to express it in rem. The tool does not inspect a page's computed styles, so match the actual project baseline yourself.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
How to use this tool
Enter pixels and the root font size in pixels. Unlike parent-relative em, rem uses a root basis; use the configured value rather than assuming a universal default.
Results and examples
24 px at a 16 px root becomes 1.5 rem. At a 20 px root it becomes 1.2 rem, making the chosen basis part of the result.
Worked example
24 px at a 16 px root becomes 1.5 rem. At a 20 px root it becomes 1.2 rem, making the chosen basis part of the result.
Limitations
- Computed site styles and user zoom preferences are not read.
- Responsive breakpoints and appropriate typography sizes are not decided.
Fields
| Field | Guidance and constraints |
|---|---|
| Pixels | Accepted range: -10000–10000 · Input step: 0.01 |
| Root font size (px) | Accepted range: 1–64 · Input step: 0.5 |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
How many rem are 24 px?
24 px at a 16 px root becomes 1.5 rem. At a 20 px root it becomes 1.2 rem, making the chosen basis part of the result.
Can I assume every site uses a 16 px root?
Computed site styles and user zoom preferences are not read. Responsive breakpoints and appropriate typography sizes are not decided.
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