Opacity vs RGBA: Which One is Better in CSS?

CSS, i.e., Cascading Style Sheet, is the fundamental part of the modern web development process that adds the design flexibility and interactivity to the web development.

CSS provides a number of properties for various page layout designs, adjust colours and fonts, add effects to images, etc. The important aspect of any web design is to set the most pleasing colour layouts. Especially, transparent colour is the most useful and unique property in CSS that makes background elements visible from another page’s top element. We can apply transparent colours on any element.

Opacity and rgba() are not only the main elements for setting transparency on any element but also the most confusing one for the web designers. I’ve come up with an easy comparison guide of opacity vs RGBA for you to understand the difference.

What is Opacity?

The opacity is a property which specifies the transparency level of a particular element through CSS. The requirement for opacity value varies between 0 and 1.

How does it work?

For instance, to achieve 30% transparency for the particular element, we need to set the opacity value as 0.3.
Check out the example for opacity that applies opacity in the class of black coloured div which contains the text.

Example output of 30% opacity:

What is RGBa()?

The rgba() defines colours using the red-green-blue-alpha value.

The RGB specifies the intensity of the red, green and blue colours between 0 and 255, or as a percentage value between 0% and 100%.

‘A’ stands for alpha in rgba() which defines the opacity as a number between 0.0 and 1.0. Here, 0.0 identifies ‘fully transparent’ and 1.0 is for ‘fully opaque’.

How does it work?

For instance, to achieve 30% transparency for the particular element, we need to set the alpha value as 0.3.

Check out the example for rgba() that specifies RGB value as 0 that means black and alpha value as 0.3.

Example output of 30% alpha:

Opacity vs RGBA

Though both elements are used for the transparency of an element, there is some basic but important difference between rgba and opacity that makes them work differently.

The primary difference is, the opacity applies to its sub-elements too. In contrast, rgba() applies the transparency of the colour to that particular element only.

For example, opacity is set to the div element that contains text and has a border. Then, the opacity of a colour element will be applied to border colour, text colour as well as the background colour. On the other hand, the rgba() affects transparency only for a single declaration as mentioned below.

Sample HTML code for the above output:

Sample CSS Code:

In the opacity property, transparency is applied to every sub child of a parent element like border, and text. In contrast, rgba is only applied to the div.

Which one is better: Opacity or rgba?

Although both opacity and rgba work for the same transparency concept, designers often get confused about choosing one among the two!

As I mentioned, basically both are not the same thing. Hence, it always depends on one’s requirement of the opacity level. It is recommended to use rgba as it provides functionality to apply opacity based on the single element, but if one needs to apply transparency on child elements also then in that scenario, use the opacity property.

That’s all!

Easy to understand, right?

If you have any question regarding the difference of opacity vs RGBa, do mention them in the Comments section below.

I would be happy to help.

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Thank You.