WCAG 2.1 · Level AA · Perceivable
WCAG 1.2.4 — Captions (Live), explained with examples
Live audio in synchronised media must have captions. Live webinars, town halls, and customer support video calls without live captions exclude deaf and hard-of-hearing participants in real time.
- Number
- 1.2.4
- Level
- AA
- Principle
- Perceivable
- Guideline
- 1.2 Time-based Media
Why this criterion exists
Live webinars, town halls, and customer support video calls without live captions exclude deaf and hard-of-hearing participants in real time.
If you only remember one thing: live audio in synchronised media must have captions. Everything else on this page is detail.
Who feels it when this fails
Accessibility criteria sometimes feel abstract until you see who pays the cost when a site ignores them. Captions (Live) affects:
Deaf and hard-of-hearing users
Users in noisy or sound-off environments
How sites typically fail it
These are the patterns we see week after week. None are intentional — they are accidents of how teams build interfaces under deadline. Knowing the failure modes is the fastest path to writing them out of your component library.
Live webinars without a captioning service
Town halls relying on ad-hoc volunteer typists
How to test for it
Spot-check live events; ensure captions are visible to attendees, not only to organisers.
Automated scanners catch this criterion most of the time, but never all of the time. Manual testing with the keyboard and a screen reader closes the gap.
A code fix you can copy
Use a captioning service appropriate to your platform; auto-captions are acceptable as a baseline but human captioners are better for technical content.
The problem
Live webinar starts at 14:00. No captions configured.The fix
Live webinar with Otter.ai / Microsoft Stream / Zoom live transcription enabled and visible to all attendees.Use a captioning service appropriate to your platform; auto-captions are acceptable as a baseline but human captioners are better for technical content.
Other Perceivable criteria
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