The <dimension> CSS data type represents a <number> with a unit attached to it, for example 10px.

CSS uses dimensions to specify distances (<length>), durations (<time>), frequencies (<frequency>), resolutions (<resolution>), and other quantities.


The syntax of <dimension> is a <number> immediately followed by a unit which is an identifier. Unit identifiers are case insensitive.


Valid dimensions

12px      12 pixels
1rem      1 rem
1.2pt     1.2 points
2200ms    2200 milliseconds
5s        5 seconds
200hz     200 Hertz
200Hz     200 Hertz (values are case insensitive)

Invalid dimensions

12 px       The unit must come immediately after the number.
12"px"      Units are identifiers and therefore unquoted.
3sec        The seconds unit is abbreviated "s" not "sec".


CSS Values and Units Module Level 5
# dimensions

Browser compatibility

BCD tables only load in the browser

See also