CSS Length Units
Introduction
A CSS distance measurement is a number immediately followed by a length unit (px, em, pc, in, …)
CSS supports a number of length measurements units. They are absolute or relative.
Syntax
- valueunit
- 1em
Parameters
| Unit | Description |
|---|---|
| % | Define sizes in terms of parent objects or current object dependent on property |
| em | Relative to the font-size of the element (2em means 2 times the size of the current font) |
| rem | Relative to font-size of the root element |
| vw | Relative to 1% of the width of the viewport* |
| vh | Relative to 1% of the height of the viewport* |
| vmin | Relative to 1% of viewport's* smaller dimension |
| vmax | Relative to 1% of viewport's* larger dimension |
| cm | centimeters |
| mm | millimeters |
| in | inches (1in = 96px = 2.54cm) |
| px | pixels (1px = 1/96th of 1in) |
| pt | points (1pt = 1/72 of 1in) |
| pc | picas (1pc = 12 pt) |
| s | seconds (used for animations and transitions) |
| ms | milliseconds (used for animations and transitions) |
| ex | Relative to the x-height of the current font |
| ch | Based on the width of the zero (0) character |
| fr | fractional unit (used for CSS Grid Layout) |
Remarks
-
A whitespace cannot appear between the number and the unit. However, if the value is 0, the unit can be omitted.
-
For some CSS properties, negative lengths are allowed.
