CSS Length Units

This section defines the supported length units for CSS attributes. Unless otherwise specified, the length units are supported as of Microsoft® Internet Explorer 3.0 or later. An asterisk (*) indicates the length unit is available as of Internet Explorer 4.0 or later.

Relative length units

em ^* The height of the element's font.

ex ^* The height of the letter "x".

px Pixels.

% Percentage.

Absolute length units

in Inches (1 inch = 2.54 centimeters).

cm Centimeters.

mm Millimeters.

pt Points (1 point = 1/72 inches).

pc Picas (1 pica = 12 points).

Relative length units
em ^*	The height of the element's font.
ex ^*	The height of the letter "x".
px	Pixels.
%	Percentage.
Absolute length units
in	Inches (1 inch = 2.54 centimeters).
cm	Centimeters.
mm	Millimeters.
pt	Points (1 point = 1/72 inches).
pc	Picas (1 pica = 12 points).

Measurements and positions in cascading style sheets (CSS) properties are indicated in length units. Internet Explorer supports two types of length units: relative and absolute.

A relative length unit specifies a length in relation to another length property. Relative length units scale better from one output device to another, such as from a monitor to a printer.

An absolute length unit specifies an absolute measurement, such as inches or centimeters. Absolute length units are useful when the physical properties of the output device are known.