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PX ↔ REM ↔ VW Converter

Convert between pixels, rem, and viewport width units instantly. Essential for responsive design.

Quick Values (click to convert)

Understanding CSS Units: PX vs REM vs VW

Choosing the right CSS units is crucial for building responsive, accessible websites. Here's when to use each:

Pixels (px)

Pixels are fixed-size units. They provide precise control but don't scale with user preferences. Use pixels for elements that should remain a fixed size, like borders or shadows.

REM Units

REM stands for "root em" and is relative to the root element's font size (usually 16px). REM units scale when users change their browser's default font size, improving accessibility.Use rem for typography, spacing, and most layout properties.

Viewport Width (vw)

1vw equals 1% of the viewport width. Use vw for fluid typography that scales with screen size, or for elements that should be a percentage of the screen width.

Formula Reference

  • px to rem: rem = px ÷ base font size
  • rem to px: px = rem × base font size
  • px to vw: vw = (px ÷ viewport width) × 100