CSS Aspect Ratio it's finally here


The long awaited CSS Aspect ratio is finally available to make our lives easier.

1 Feb, 2021 ยท 3 min read

If youโ€™re a front-end developer, you must have looked up โ€œCSS Aspect Ratioโ€ more than once.

One of these things one would expect to be existing in CSS for a long time, but it was not! (Well, not really)

There are some hacks to achieve it.

But not a proper aspect-ratio solution, until now, that is!

Chrome just got support for the aspect-ratio property.

To give you an example of how it works:

CSS aspect-ratio demo

Using the CSS aspect-ratio

The syntax for the aspect-ratio is pretty simple.

aspect-ratio: width / height;

Alternatively, you have some CSS basics like:

aspect-ratio: inherit;
aspect-ratio: initial;
aspect-ratio: unset;

To test it out, letโ€™s make a resizable box to test how it works.

<div class="container"></div>

Inside the container, we will place two boxes that will have their own aspect ratios

Box 1 will have an aspect ratio of 1/1 And Box 2 will have a 16/9 aspect ratio.

<div class="container">
  <div class="box box1"></div>
  <div class="box box2"></div>

First, weโ€™ll start by styling the container. We want it to wrap the elements inside but add the CSS Resize property.

.container {
  display: flex;
  gap: 16px;
  resize: horizontal;
  overflow: auto;

Then we can move to our generic box styling. This will be the styling that each box will get.

.box {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: #fff;

As you can see, this is mainly used to center the content inside the boxes and give them a bigger font.

Now onto the magic part ๐Ÿช„.

CSS square aspect-ratio 1/1

For our first box, we will use a square aspect ratio. We can achieve this by using the following CSS.

.box1 {
  aspect-ratio: 1 / 1;
  background: #06d6a0;
  flex: 1;

This will provide us with a square box that can grow in size.

CSS rectangle aspect-ratio 16/9

The second box will have a 16/9 aspect ratio, which we can achieve by the following CSS.

.box2 {
  aspect-ratio: 16 / 9;
  background: #ef476f;
  flex: 1 0 auto;

Now we get the following result which you can test out in this Codepen.

Note: Browser support is not big, so you might not see it behave as expected. In the beginning, I added the GIF to showcase how it works.

See the Pen CSS Aspect Ratio it's finally here by Chris Bongers (@rebelchris) on CodePen.

Browser Support

Itโ€™s still very early days for the aspect-ratio browser support. Chrome shipped it in production in version 88, and Firefox has it in beta so that you can enable it in Firefox.

CSS aspect-ratio browser support

Thank you for reading, and letโ€™s connect!

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