CSS opacity Property Reference

The CSS opacity property is a standard property in CSS Color. Review its formal syntax, computed behavior, and practical declarations.

Updated 2026-08-12

opacity overview

The CSS opacity property is a standard property in CSS Color. Review its formal syntax, computed behavior, and practical declarations.

The property is not inherited by default. Use an explicit global keyword when inheritance is intended.

Syntax and formal definition

opacity formal syntax

Field	Value
Formal syntax	<opacity-value>
Initial value	1
Applies to	allElements
Inherited	No
Percentages	mapToRange0To1
Computed value	specifiedValueNumberClipped0To1
Animation type	byComputedValueType
Media	visual
Specification group	CSS Color
Status	Standard

Practical examples

These declarations demonstrate valid ways to set opacity. The initial and inherit global keywords remain available even when a property-specific value is preferable.

opacity live example

CSS

.reset-example {
  opacity: initial;
}

.inherit-example {
  opacity: inherit;
}

@supports (opacity: 0.5) {
  .supported {
    opacity: 0.5;
  }
}