WCAG Guideline 1.2.4: Captions (Live) Explained
Estimated read time: 8–10 minutes
Guideline 1: Perceivable
The first principle of WCAG, Perceivable, ensures that information and user interface components must be presented to users in ways they can perceive. This means content can’t be invisible to all of a user’s senses—whether they are seeing, hearing, or feeling the content through assistive technology.
Guideline 1.2: Time-based Media
Guideline 1.2 focuses on making time-based media—like audio and video—accessible to everyone. This includes providing alternatives such as transcripts, captions, and audio descriptions so users with different abilities can access the content.
What Is Guideline 1.2.4 Captions (Live)?
"Captions are provided for all live audio content in synchronized media."
Guideline 1.2.4 is a Level AA requirement in the Web Content Accessibility Guidelines (WCAG) .
- All live video content with audio must have captions.
- Captions should accurately reflect spoken dialogue and important sounds in real time.
- Captions help users who are deaf, hard of hearing, or in environments where audio can’t be played.
This ensures everyone can access the information in your live videos, regardless of hearing ability or environment.
Why Does It Matter?
- Inclusivity: Captions make live video content accessible to users who are deaf or hard of hearing.
- Legal Compliance: This is a Level AA requirement in WCAG 2.2 and referenced in accessibility laws worldwide.
- Usability: Captions help all users in noisy or quiet environments, or when audio is muted.
For more, see WebAIM's captions guide and University of Washington's Captions Accessibility Checklist .
What Needs Captions?
- Live video content with audio (webinars, conferences, events)
- Online courses and live training sessions
- Live news and broadcasts
All such media must have accurate, real-time captions.
How to Provide Captions
- Use live captioning services or software to create real-time captions
- Ensure captions are as accurate and timely as possible
- Include speaker identification and important non-speech sounds
- Make captions easy to enable and access
For more, see the W3C's captions docs .
Common Mistakes to Avoid
- No captions for live video content
- Inaccurate or delayed captions
- Captions that are out of sync with audio
- Hiding captions or making them hard to enable
Audit your site regularly and use accessibility checkers to ensure all live video content has proper captions. For more, see the FCC's guide to Closed Captioning on Television .
Differences Between A, AA, and AAA for Guideline 1.2.4 in WCAG 2.2
- Level A: No requirement for 1.2.4.
- Level AA: Requires captions for all live audio content in synchronized media. This is the core requirement for 1.2.4 and is mandatory for AA conformance.
- Level AAA: For Guideline 1.2.4, there are no additional requirements beyond Level AA in WCAG 2.2. Meeting Level AA for this guideline also satisfies Level AAA.
For more, see the W3C’s official documentation for 1.2.4 Captions (Live) .
Quick Checklist
- All live video content with audio has captions
- Captions are accurate and timely
- Captions include speaker identification and important sounds
- Captions are easy to enable and access
- Tested with users and assistive technology
Summary
Guideline 1.2.4 is essential for making live video content accessible to everyone. By providing accurate, real-time captions, you support users with disabilities, improve usability, and meet legal requirements. Make live captioning a standard part of your event planning process.