This criterion ensures that audio does not begin playing automatically in a way that interferes with a user’s ability to perceive, navigate, or understand a page. When sound starts without warning, users may be startled, distracted, or unable to hear other important audio, particularly assistive technology output.
In this context, autoplay includes any audio that begins playing without a deliberate user action, whether triggered by an HTML autoplay attribute, JavaScript, or a third-party embed. It applies to background music, marketing videos, advertisements, and any other sound that starts on page load.
This requirement exists because users cannot rely on speed, precision, or perfect hearing to regain control once unexpected audio begins.
WCAG Success Criterion
1.4.2 Audio Control (Level A)
If audio plays automatically for more than three seconds, a mechanism must be available to pause or stop the audio, or to control the audio volume independently from the system volume.
What This Means in Practice
WCAG does not prohibit autoplaying audio outright, but it places strict conditions on it. If sound plays automatically and lasts longer than three seconds, users must be given an immediately available, accessible way to stop, pause, mute, or adjust the volume.
In practice, the safest and most robust approach is to require a clear user action, such as clicking a Play button, before any audio begins. Doing so eliminates interference with assistive technologies and avoids compliance risk entirely.
Why This Matters
Screen reader users depend on audio output to navigate a page. When other sounds start automatically, they can overlap with screen reader speech, making both the content and the controls difficult or impossible to understand.
Because screen reader users explore pages by listening, autoplaying audio can also prevent them from locating the control needed to stop it. For this reason, WCAG strongly discourages autoplaying audio, especially on page load, and encourages authors to start sound only after users choose to do so.
Who Is Affected
This issue most directly affects users who:
- Use screen readers or text-to-speech software
- Have low vision and rely on audio feedback
- Have cognitive or attention-related disabilities
- Access content in quiet, shared, or noise-sensitive environments
Unexpected audio can disrupt orientation, comprehension, and task completion.
Acceptable Ways to Meet the Requirement
This criterion can be satisfied in one of the following ways:
Audio or video playback begins only after a user-initiated action.
Automatically playing audio stops within three seconds.
Audio that plays longer than three seconds provides a clearly visible, keyboard-accessible control to pause, stop, mute, or adjust volume.
Requiring a user action to start audio is the most reliable solution and avoids conflicts with assistive technologies.
Muted Video vs Audio Autoplay
Muted autoplaying video does not violate SC 1.4.2, because no audio is present. This is why muted hero videos or background videos are often allowed.
However, the moment audio is introduced, either immediately or after a delay, the criterion applies. If sound plays without user initiation and lasts longer than three seconds, controls are required.
Concrete Examples
Failing example
A marketing video loads on the homepage and begins playing with sound immediately. No pause or mute controls are visible upon load. Users must search the page while audio is already playing.
Passing example
A video loads in a paused state with a visible Play button. Audio begins only after the user activates the control.
Passing (with autoplay)
Audio begins automatically but stops within three seconds, or a clearly visible, keyboard-accessible pause/mute control is available immediately.
Common Failures
This criterion fails when:
- Audio or video plays automatically for more than three seconds with no accessible control
- Short audio loops continuously
- Controls exist but are hidden, keyboard-inaccessible, or difficult to locate
- Third-party embeds (ads, media players) autoplay sound without user control
A common misconception is:
“If users can just turn their volume down, it’s fine.”
This is false. Volume control must be available within the content itself, not only at the system level.
Rule Description
Audio and video elements must not autoplay sound for more than three seconds unless users are given an immediate, accessible way to pause, stop, mute, or control the audio volume.
The Algorithm (In Simple Terms)
This rule evaluates audio and video behaviour as follows:
If an <audio> or <video> element has no source, the result is undefined.
If audio can autoplay and no control mechanism is available, the rule fails.
If audio plays automatically for less than three seconds but loops, the rule fails.
If audio plays automatically and accessible controls are provided, the rule passes.
If playback begins only after a user action, the rule passes.
How to Test This
Load the page with a screen reader running. If any audio overlaps with screen reader output before you take an action, investigate autoplay immediately.
Also, test with the keyboard alone. If audio starts playing, ensure the pause or mute control is visible, reachable by Tab, and operable without delay.
Automated tools can flag obvious autoplay cases, but manual testing is essential for this criterion.
Related WCAG Techniques and Failures
- G60: Playing a sound only on user request
- G170: Providing a control to pause or stop audio
- F23: Failure due to playing audio automatically without user control
Wrapping Up
Unexpected audio removes control from the user and interferes with assistive technologies. If sound plays without warning and users cannot immediately stop it, the experience fails this criterion. Requiring a user action to start audio is the simplest, safest, and most accessible solution.
