The opacity CSS property sets the opacity of an element. Opacity is the degree to which content behind an element is hidden, and is the opposite of transparency.

Try it



opacity: 0.9;
opacity: 90%;

/* Global values */
opacity: inherit;
opacity: initial;
opacity: revert;
opacity: revert-layer;
opacity: unset;



A <number> in the range 0.0 to 1.0, inclusive, or a <percentage> in the range 0% to 100%, inclusive, representing the opacity of the channel (that is, the value of its alpha channel). Any value outside the interval, though valid, is clamped to the nearest limit in the range.

Value Meaning
0 The element is fully transparent (that is, invisible).
Any <number> strictly between 0 and 1 The element is translucent (that is, content behind the element can be seen).
1 (default value) The element is fully opaque (visually solid).


opacity applies to the element as a whole, including its contents, even though the value is not inherited by child elements. Thus, the element and its children all have the same opacity relative to the element's background, even if they have different opacities relative to one another.

Using opacity with a value other than 1 places the element in a new stacking context.

When opacity value is set to 0, the element and all of its children are not visible; however, they still register pointer events. This can be controlled with the CSS pointer-events property.

To change the opacity of a background only, use the background property with a color value that allows for an alpha channel. For example:


background: rgba(0, 0, 0, 0.4);

Accessibility concerns

If text opacity is adjusted, it is important to ensure that the contrast ratio between the color of the text and the background the text is placed over is high enough that people experiencing low vision conditions will be able to read the content of the page.

Color contrast ratio is determined by comparing the luminosity of the opacity-adjusted text and background color values. In order to meet current Web Content Accessibility Guidelines (WCAG), a ratio of 4.5:1 is required for text content and 3:1 for larger text such as headings. Large text is defined as 18.66px and bold or larger, or 24px or larger.

Formal definition

Initial value1
Applies toall elements
Percentagesmap to the range [0,1]
Computed valueThe same as the specified value after clipping the <number> to the range [0.0, 1.0].
Animation typeby computed value type

Formal syntax

opacity = 

<alpha-value> =
<number> |


Setting opacity

The following example demonstrates how the opacity property changes the opacity of the entire element and content, thus making the text very hard to read.



<div class="light">You can barely see this.</div>
<div class="medium">This is easier to see.</div>
<div class="heavy">This is very easy to see.</div>



div {
  background-color: yellow;
  font-weight: bold;
  font-size: 130%;
.light {
  opacity: 0.2; /* Barely see the text over the background */
.medium {
  opacity: 0.5; /* See the text more clearly over the background */
.heavy {
  opacity: 0.9; /* See the text very clearly over the background */


Setting opacity on hover

In the following example opacity is changed on hover, so the striped background image on the parent element shows through the image.



<div class="wrapper">
    alt="MDN Dino"
    class="opacity" />



img.opacity {
  opacity: 1;

img.opacity:hover {
  opacity: 0.5;

.wrapper {
  width: 200px;
  height: 160px;
  background-color: #f03cc3;
  background-image: linear-gradient(
    transparent 50%,
    rgba(255, 255, 255, 0.5) 50%
  background-size: 20px 20px;



CSS Color Module Level 4
# transparency

Browser compatibility

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