edit 09 Nov 2013

Keeping responsive aspect ratio

What should you do if you need to make a responsive YouTube video? That is, when you shrink your window your content should properly adapt and do not look silly like having 480x640 instead of 480x320 (for 4:3 aspect ratio).

It is natural to use a 100% width on your content, but the sad thing is that iframe doesn’t count content height and it will be set to some default value (like 150px, depends on browser).

Actually there is a simple way to make it work. We will add a dummy div placeholder right before our naughty content that will act like spacer in our layout.

<div class="container">
  <div class="placeholder"></div>
  <iframe class="content"

And then we need to fix our content with position: absolute to display on top of the placeholder:

.container {
  position: relative;

.placeholder {
  padding-bottom: 75%; /* 100% / (4 / 3) = 75% */

.content {
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;

Done! So that if you want to fit a 16:9 video you should set your placeholder height to 100% / (16 / 9) ≈ 56%.

I use this technique in my blog to fit video and iframe’s in various screen sizes. Hope it will help you too.

Have a nice day!