CSS Unit Converter

By default 1rem = 16px, because browsers default the root (html) font size to 16px. If a page sets a different root font size, 1rem equals that size instead — adjust the 'Root font size' field above to match your project.

rem is always relative to the root (html) element's font size, so it stays consistent everywhere on a page. em is relative to the current element's own (often inherited) font size, so the same em value can render differently depending on where it's used — useful for scaling within a component, but easy to compound unexpectedly when nested.

1vw equals 1% of the viewport's width and 1vh equals 1% of the viewport's height, both measured in CSS pixels. They're commonly used for full-bleed layouts and typography that scales with the window/device size rather than a parent element.

CSS defines physical units at a fixed 96px-per-inch reference: 1in = 96px, 1pt = 1/72in (~1.333px), and 1pc = 12pt = 1/6in (16px). These are exact conversions, not screen-DPI-dependent, matching the CSS Values and Units specification.