Responsive iframes

Building responsive iframes can be frustrating. Don't let one break your beautifully laid out responsive site. Learn how to build responsive iframes the right way with just CSS using the intrinsic ratio technique to create an aspect ratio box.
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Responsive iframes was originally published on Mar 19, 2014 and has recently been updated on Aug 6, 2020 to reflect emerging trends.

Learn to create responsive iframes with clean & simple CSS by making an aspect ratio box using intrinsic ratios. Transform any iframe to become responsive that’ll keep its aspect ratio when resized.

tl;dr

.iframe-container {
  overflow: hidden;
  // 16:9 aspect ratio
  padding-top: 56.25%;
  position: relative;
}

.iframe-container iframe {
   border: 0;
   height: 100%;
   left: 0;
   position: absolute;
   top: 0;
   width: 100%;
}
<div class="iframe-container">
  <iframe src="//www.youtube.com/embed/KMYrIi_Mt8A" allowfullscreen></iframe>
</div>

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Step-by-Step Guide to Responsive iframes

Building responsive iframes is a wright of passage in the web development world. The problem, iframes set to 100% become fluid, not responsive. The aspect ratio doesn’t stay the same since only the width scales. 

So how do you make an iframe responsive? It’s a common question with a simple CSS-only solution. Use the intrinsic ratio technique to create an aspect ratio box. Check out the example below.

How to make an iframe responsive?
  1. Step 1: Get the iframe embed code and paste into your document
  2. Step 2: Set the height & width attributes to 100% (optional, can be handled via CSS)
  3. Step 3: Absolute position the iframe within a container
  4. Step 4: Add padding-top to the container

Don’t forget to lazy-load your iframes. In addition to making your iframes responsive, you’ll want to lazy-load them using the loading attribute. This improves page load times, enhances the user experience, and increases your search engine rankings. Learn more about how to lazy-load iframes.

This example demonstrates how to embed a responsive (16:9) YouTube video using an iframe snippet. It creates an aspect ratio box that will resize proportionally based on screen size. Try it out by resizing your browser window.

Example Aspect Ratios

padding-top: 56.25%; /* 16:9 aspect ratio */
padding-top: 75%; /* 4:3 aspect ratio */
padding-top: 66.66%; /* 3:2 aspect ratio */
padding-top: 62.5%; /* 8:5 aspect ratio */
padding-top: 100%; /* 1:1 aspect ratio */

What’s an aspect ratio? An aspect ratio of an element describes the proportional relationship between its width and its height. Two common video aspect ratios are 4:3 (the universal video format of the 20th century), and 16:9 (universal for HD television and European digital television, and for YouTube videos).

The Magic of Responsive iframes

The secret sauce to making iframes responsive is something called the intrinsic ratio technique (aka. an aspect ratio box).

You’ve spent countless hours designing and building the perfect responsive site. One problem — iframes. Proportionally resizing (aka. responsive iframes) these pesky little windows to another world can be frustrating. It’s easy enough to make an iframe’s width span 100% of its container. Yet making the height resize accordingly can be tricky.

So how do you keep from blowing your top trying to make an iframe responsive? Hint: it doesn’t require any JavaScript, just a simple CSS technique!

Native responsive iframes are coming! There is the experimental intrinsicsize attribute that I could imagine being quite nice for iframes in addition to images. Plus the aspect-ratio in CSS which could default to use the width and height attributes on the element, which I hope would extend to iframes.

The Intrinsic Ratio Technique (aka. aspect ratio box)

Aspect ratio box to create responsive iframes
For the visual learner, here’s how creating responsive iframes work. We have set a default padding-top here, but in reality, the ratio of the sizing of an embed change per provider and even per embed. We need to calculate the padding-top and then add this as a style to the responsive wrapper.

In Resize Videos Proportionally, I went over how to use the intrinsic ratio technique to make your embedded videos responsive. We’ll use that same method to create an aspect ratio box to make any iframe, YouTube & Vimeo video or Google Map responsive. Only dependency is you know the aspect ratio (width x height) of the iframe.

Do not use JavaScript to make iframes responsive. I cringe every-time I see someone using JS when a simple CSS solution exists — even if it’s “light-weight”, it’s not needed. Worse, they often have issues with cross-browser compatibility & bugginess. The intrinsic ratio technique is a much simpler way to implement cross-browser compliant responsive iframes.

In-depth Guide to Making iframes Responsive

When embedding iframes for content such as videos, most services like YouTube and Vimeo will provide you a snippet of code like the one below:

<iframe width="560" height="315" src="//www.youtube.com/embed/KMYrIi_Mt8A" allowfullscreen></iframe>

Notice I removed the frameborder attribute. If you’re using HTML5, that attribute is no longer supported.

First of all, remove the width and height attributes. Keeping those attributes forces the content to stay at that size regardless of the screen size. This causes problems in responsive layouts when the screen size is smaller than the width of the iframe. Though we could use CSS to force the size, why have them if their not being used — less code is beautiful code.

<iframe src="//www.youtube.com/embed/KMYrIi_Mt8A" allowfullscreen></iframe>

Next, let’s add a container with a class around the iframe:

<div class="iframe-container">
  <iframe src="//www.youtube.com/embed/KMYrIi_Mt8A" allowfullscreen></iframe>
</div>

Now, we add a little touch of CSS magic to make the iframe responsive. The same way we did in the “Resize Videos Proportionally with Intrinsic Ratios“.

.iframe-container {
  overflow: hidden;
  padding-top: 56.25%;
  position: relative;
}

.iframe-container iframe {
   border: 0;
   height: 100%;
   left: 0;
   position: absolute;
   top: 0;
   width: 100%;
}

/* 4x3 Aspect Ratio */
.iframe-container-4x3 {
  padding-top: 75%;
}

IMPORTANT: Don’t forget to apply an aspect ratio class to your iframe. If you don’t, it could cause them iframe to disappear.

That it! Simple, huh? Your iframe should now proportionally resize based on the browser size. Here’s a breakdown of how it works:

Highlights to Making iframes Responsive

  • It’s key to specify the containers position to be relative. This allows us to absolute position the iframe within it, which is needed to make it responsive.
  • The padding-top value is calculated based on the aspect ratio of your content. Instead of adding it to the intrinsic-container class, we added separate classes that can be appended to that element depending on the type of content you’re embedding. I prefer doing this so I’m not duplicating the container code for different aspect ratios. To find the aspect ratio of a container, use this formula: height ÷ width = aspect ratio
  • height is set to 0 because padding-bottom gives the iframe it’s height.
  • Using overflow: hidden is important because it ensures if any content does protrude outside of the container, it will be hidden and avoid screwing up the site’s layout.
  • Like with most absolute positioned elements, we need to set the top and left properties so the iframe get’s put in the right place.
  • Finally, width and height are set to 100% so the iframe takes up 100% of the containers’ space.

Using SASS?

If you’re using SASS, use this function to find the ratio or padding-bottom of the parent container:

/**
 * Ratios
 * Returns the ratio for specified dimensions.
 */
@function ratio($width, $height) {
  return percentage( $height / $width);
}

Taking that one step further, you can create a mixin to generate ratio classes:

@mixin generateRatios($width, $height, $prefix: "ratio-") {
  $class-name: $prefix + $width + "x" + $height;

  .#{$class-name} {
    padding-bottom: ratio($width, $height);
  }
  // Output example: .ratio-16x9 {}
}

@include generateRatios(16,9); // 16x9
@include generateRatios(4,3);  // 4x3

We can use this same technique to make other types of embedded content responsive like Google Maps & Calendars. Basically, anything that uses a iframe using only CSS! If you don’t have access to edit the site stylesheets directly, here’s a nifty tool that will generate responsive embed codes for you.

Using a CSS Framework?

A lot of projects now will use some kind of CSS framework like Bootstrap, Foundation or Materialize to help with keep styling uniform throughout the project. Some frameworks already have classes that will do exactly the same as what’s above. Check out some of the examples below.

Responsive iframes in Bootstrap

Bootstrap 3.2+, use the predefined class .embed-responsive and an aspect ratio class modifier like .embed-responsive-16by9 (more listed below). This aspect ratio modifier will add the padding-top with different percentages depending on the given modifier class, then give your iframe the .embed-responsive-item class.

<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="https://www.youtube.com/embed/K1K8s-tQGqY" allowfullscreen></iframe>
</div>

Other responsive iframe ratios in Bootstrap:

  • .embed-responsive-21by9
  • .embed-responsive-16by9
  • .embed-responsive-4by3
  • .embed-responsive-1by1

You can, of course, create your own modifier class:

.embed-responsive-10by3 {
   padding-top: 30%;
}

Responsive iframes in Materialize

If you are using Materialize CSS, then you don’t need your own classes either. Just add the .video-container class to your wrapper:

<div class="video-container">
  <iframe src="https://www.youtube.com/embed/K1K8s-tQGqY" frameborder="0" allowfullscreen></iframe>
</div>

Responsive iframes in Foundation

<div class="responsive-embed">
  <iframe src="https://www.youtube.com/embed/K1K8s-tQGqY" frameborder="0" allowfullscreen></iframe>
</div>

Aspect ratio modifier classes are set in your $responsive-embed-ratios map in your Foundation settings file:

$responsive-embed-ratios: (
  default: 16 by 9,
  vertical: 9 by 16,
  panorama: 256 by 81,
  square: 1 by 1,
);

So you’re determined to use JS?

What if you don’t know the aspect ratio? Let’s say you have content authors creating interactives with each having different dimensions. Without knowing the aspect ratio of the iframe, it’s not easy to implement the intrinsic ratio technique.

You can overcome this problem by using JS:

// Find all iframes
var $iframes = $( "iframe" );

// Find & save the aspect ratio for all iframes
$iframes.each(function () {
  $( this ).data( "ratio", this.height / this.width )
    // Remove the hardcoded width & height attributes
    .removeAttr( "width" )
    .removeAttr( "height" );
});

Responsive iframes are awesome.

Say Goodbye to embedded content breaking your layouts with the intrinsic ratio technique. We’ve walked through how just a little bit of code can easily make your iframes and other embedded content responsive friendly.

How do you embed third-party content on your responsive website? Do you have a nifty technique or trick to accomplish responsive embedded content? What about your workflow for embedding content like Google Maps, YouTube, etc? I’d love to hear from you. Comment below with your thoughts.

Additional Resources

Check out these other great articles about making embedded content responsive:

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149 Comments on “Responsive iframes”

mick

# Jul 16, 2020

thank you…a very easy fix…with your code help..works perfect

Barbsketch

# Jun 23, 2020

Hi! This solved the problem of my video being larger than the viewing screen. However, I am dealing with a 9:16 ratio *vertical* video. I have huge black bars on either side of the video that I can’t seem to get rid of by various means. Do you have any suggestions? Maybe I should be using a different padding percentage as my aspect ratio is flipped? I tried with %177.78 and it didn’t work…

The URL of the video, although this might have changed by the time you read this:

http://barbchoit.com/platforms-2020-video-sketch/

(black bars not an issue in firefox)

Thanks!

Ajay Chauhan

# Jun 2, 2020

Hi there,
I was searching for How to make iframes responsive. and here I got it and you have explained it very well. this is very helpful for me.
Thanks

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