REM to PX Converter Online - CSS Unit Calculator
Convert CSS px and rem values in either direction with a configurable root font size.
About this tool
Enter a value such as 24px or 1.5rem. The second field sets the root pixel size and defaults to 16 when it is empty or not numeric.
How to use
- Enter the value in the format described by the tool.
- Run the conversion or calculation in your browser.
- Review and copy the generated result.
Features
- PX to REM conversion.
- REM to PX conversion.
- Configurable positive root size.
Common use cases
- Translate design measurements into rem.
- Check CSS spacing against a root size.
- Convert existing rem values to pixels.
Common issues and tips
- The input must include px or rem.
- Actual rendered rem size depends on the page root font size.
Privacy
Processing runs locally in your browser. Input is not uploaded to Tools12345.
Frequently asked questions
What is the default root size?
16 pixels.
Can decimals be used?
Yes.
Does this read my website CSS?
No, enter the root size manually.