CSS <frequency> Data Type


The CSS <frequency> data type represents a frequency dimension, such as the pitch of a speaking voice. It is not currently used in any CSS properties, but it is defined in the CSS specifications in case it is needed in the future.

Frequency values are dimensions denoted by <frequency>. They are specified as a number followed by one of the following units:

  • Hz (Hertz)
  • kHz (Kilohertz)

For example, valid frequency values include:


As with all CSS dimensions, there is no space between the unit literal and the number.

The <frequency> data type is a <dimension>, which means that it can be used in the calc() function. For example, the following expression would evaluate to 16Hz:

calc(12Hz + 4Hz)

However, since there are no CSS properties that currently accept frequency values, this expression would be useless.

It is possible that the <frequency> data type will be used in future CSS properties, such as properties that control the pitch of audio effects. However, until that time, it is a dormant data type.


property: <frequency>;


  • HzFrequency in hertz, represents the number of cycles per second.
  • kHzFrequency in kilohertz, represents the number of thousands of cycles per second (in other words, 1kHz equals 1000Hz).


Unfortunately, no CSS properties use the frequency data type yet. 

Browser Support

The following table will show you the current browser support for the CSS frequency data type.

Edge Chrome Firefox Opera Safari
Tablets / Mobile
Chrome Firefox Opera Safari Samsung Webview

Last updated by CSSPortal on: 7th October 2023