CSS Units Converter

Configure root font size, parent font size, and viewport dimensions so relative-unit conversions are transparent.

Value

From

Root px

Parent px

Viewport width

Viewport height

—rem, em, vw, and vh depend on the explicit context above.

Runs locally in your browser. Generated CSS is not deployed or tested against your site automatically.

How to use this CSS Units Converter

Convert CSS lengths between px, rem, em, pt, vw, and vh using explicit context values. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.