CSS Unit Converter

Convert px, rem, em, %, vw and vh with configurable context.

Runs locally in your browser. No data is sent to a server.

Value

Conversions

px16

rem1

em1

vw1.1111

vh1.7778

Context

Root font sizepx

Element font sizepx

Percentage referencepx

Percentage units depend on the CSS property. Set the reference size for your use case.

Viewport widthpx

Viewport heightpx

Viewport:

CSS percentage behaviour depends on the property — width: 50% and font-size: 50% may use different reference sizes. Set the reference above for your use case.

About CSS Unit Converter

Convert CSS length values between px, rem, em, percentage, vw and vh. Set a custom root font size for accurate px-to-rem and rem-to-px calculations, configure element font size for em conversions, and adjust viewport dimensions and a percentage reference size to match your layout context. All conversions update instantly in the browser — nothing is sent to a server.