Digital Accessibility Blog

What Is Closed Captioning for Web Accessibility?

Written by Alexa | Apr 18, 2024

If your website includes multimedia, you must provide captions. That’s not just our opinion — the Department of Justice (DOJ) specifically mentions captions in its guidance on web accessibility. Omitting captions may be a violation of the Americans with Disabilities Act (ADA), the European Accessibility Act (EAA), and a number of other disability non-discrimination laws. 

But as is the case with many accessibility features, captions aren’t just for users with disabilities. Accurate captions help all users understand (and engage with) your content. In this article, we’ll answer common questions about closed captions for accessibility and provide tips for captioning your videos.

What does “closed caption" mean, exactly? 

There are two ways to present captions: Open captions, which are pre-rendered with the video (also called “burned in captions"), and closed captions, which are delivered as a toggleable script. Users can turn off closed captions — they can’t turn off open captions.

Closed captions have a number of advantages over open captions:

  • Some people may prefer to view your video without captions. Closed captions give them more control. 
  • With closed captions, users can easily translate the text to other languages, change the font size and color, or search for keywords. 
  • Screen readers (software that converts text to audio) can access closed captions. Open captions may be invisible to assistive technologies.

Open captions are better than nothing, and in some situations, you may not have an alternative. For example, certain social media websites may not support caption files. If you have the option, however, you should always use closed captions.

Related: Open Vs. Closed Captions: Which Is More Accessible?

Am I legally required to include captions for online videos?

That depends on where your business is located — but in most cases, yes. 

Title III of the ADA applies to private businesses and requires reasonable efforts to accommodate people with disabilities. While Title III doesn’t include technical criteria, the DOJ recommends testing content against the Web Content Accessibility Guidelines (WCAG).

WCAG is the international standard for digital accessibility, and many laws specifically require WCAG conformance. Unsurprisingly, the guidelines require captions for all pre-recorded audio content in synchronized media (except when the media is a media alternative for text). 

The bottom line: You must include captions for videos with important audio. WCAG doesn’t specifically require closed captions, but as we’ve discussed, closed captions provide a better user experience. 

Related: Does the ADA Require Captions for Internet Videos?

What’s the difference between captions and subtitles?

Captions include a description of all important audio. Subtitles only include spoken dialogue — they omit musical cues and sound effects.

You must provide captions, not just subtitles. However, in some situations, a video’s dialogue may be the only “important audio.” In those cases, subtitles and captions would be the same thing. 

Can I use auto-generated captions to fulfill WCAG? 

Currently, automatically generated captions aren’t accurate enough to fulfill WCAG requirements. YouTube’s automatic captions, for example, are about 60-70% accurate. 

That may sound like a fairly impressive number, but imagine watching a video and missing every third word. Would that be an acceptable experience? 

You can use automatic captions as a starting point, but review them carefully before publishing them. A better practice is to create captions from the scripts of your videos. 

Related: What’s the Acceptable Format for Media Captions and Transcripts? 

If my website has captions, do I need to include transcripts? 

Yes, you should include captions and transcripts. In terms of accessibility, these tools serve completely different audiences:

  • Captions improve experiences for people who cannot (or choose not to) listen to content.
  • Transcripts improve experiences for people who cannot (or choose not to) view content visually.

Adding transcripts to your website can be beneficial for search engine optimization (SEO), since you’re providing search engine crawlers with a large amount of useful text-based content. 

And if you’re writing captions when drafting your videos, writing transcripts shouldn’t add too much to your workload — just remember that transcripts must include descriptions of important visuals.

Related: Why Do I Need Both Transcripts And Captions for Accessibility?

I’ve added captions to my videos. Does that make them accessible?

Not necessarily. Captions are important, but they’re not the only accessibility feature to consider. For example:

This is not a comprehensive list, and for the best possible results, you’ll need to think about accessibility from the first stages of video production. Fortunately, it’s worth the effort: Following WCAG can make your video content more effective and engaging.

To learn more, download our free Video Accessibility Checklist. For help with a specific accessibility question, send us a message to connect with an expert.