Convert any CSS value between px, rem, em, vw, vh, %, pt, pc, ch, ex, cm, mm, and in. Set your base font size and viewport dimensions for accurate real-time conversion. Puro client-side.
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Our free CSS Unit Converter helps web developers and designers instantly convert between all common CSS units. Whether you need to convert px to rem for responsive design, vw to px for viewport-relative sizing, or any other combination — this tool handles it all. All calculations happen in your browser with no data sent to servers.
Set your base font size (default is 16px), enter your pixel value, select "px" as input, and the converter will instantly show the rem equivalent. For example, 16px = 1rem when the base font size is 16px.
Both em and rem are relative units based on font size. "rem" (root em) is always relative to the root element font size (usually <html>). "em" is relative to the font size of the parent element. This makes rem more predictable for consistent sizing across components.
vw (viewport width) and vh (viewport height) are relative to the browser window size. 1vw = 1% of the viewport width, and 1vh = 1% of the viewport height. They are perfect for creating responsive layouts that adapt to screen size.
Absolutely. All conversions happen entirely in your browser. No data is ever sent to our servers or stored anywhere.