Aspect ratio

CSS, Layout · Aug 14, 2022

Creates a responsive container with a specified aspect ratio.

  • Use a CSS custom property, --aspect-ratio to define the desired aspect ratio.
  • Set the container element to position: relative and height: 0, calculating its height using the calc() function and the --aspect-ratio custom property.
  • Set the direct child of the container element to position: absolute and filling it parent, while giving it object-fit: cover to maintain the aspect ratio.
<div class="container">
  <img src="" />
.container {
  --aspect-ratio: 16/9;
  position: relative;
  height: 0;
  padding-bottom: calc(100% / (var(--aspect-ratio)));

.container > * {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;

Written by Angelos Chalaris

I'm Angelos Chalaris, a JavaScript software engineer, based in Athens, Greece. The best snippets from my coding adventures are published here to help others learn to code.

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