PX / REM Calculator Documentation

Convert pixel values to rem or em units and back, based on a configurable root font size.

SiteIndex divides or multiplies your pixel value by the root font size you set (16px by default) to convert between px, rem, and em units instantly.

• Convert a design's pixel spacing into rem units for a CSS design system.
• Check what a rem value equals in pixels at a custom base font size.
• Build a quick reference table of common px-to-rem conversions.

Input

Text, files, or values entered in the browser, depending on the tool.

Output

A result shown in the browser that can be reviewed or copied where supported.

• Results depend on the input, browser, network, and external service involved.
• This tool is informational and does not replace specialist diagnostics.

Inputs for this browser-side tool are processed locally and are not sent to SiteIndex. Normal page analytics may still be collected as described in the Privacy Policy. Read the Privacy Policy.