Computed value
The computed value of a CSS property is the value that is transferred from parent to child during inheritance. It is calculated from the specified value by:
- Handling the special values
inherit
,initial
,revert
,revert-layer
, andunset
. - Doing the computation needed to reach the value described in the "Computed value" line in the property's definition table.
The computation needed to reach a property's computed value typically involves converting relative values (such as those in em
units or percentages) to absolute values. For example, if an element has specified values font-size: 16px
and padding-top: 2em
, then the computed value of padding-top
is 32px
(double the font size).
However, for some properties (those where percentages are relative to something that may require layout to determine, such as width
, margin-right
, text-indent
, and top
), percentage-specified values turn into percentage-computed values. Additionally, unitless numbers specified on the line-height
property become the computed value, as specified. The relative values that remain in the computed value become absolute when the used value is determined.
Note: The getComputedStyle()
DOM API returns the resolved value, which may either be the computed value or the used value, depending on the property.
Specifications
Specification |
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Cascading Style Sheets Level 2 Revision 2 (CSS 2.2) Specification # computed-value |