What this criterion requires
Nothing on the page may flash more than three times per second, unless the flashing is below the general flash and red flash thresholds.
Who it helps
People with photosensitive epilepsy - this criterion prevents physical harm.
Example: fails vs passes
A promo video with a strobe segment flashing 8 times per second.
The same edit with the strobe removed after failing a PEAT flash analysis.
More than 3 flashes per second risks triggering seizures - this criterion prevents physical harm.
How to meet and fix it
- Simply avoid flashing content entirely
- Vet video and ad creatives with a flash analysis tool (PEAT) before publishing
Common failures auditors find
- Strobing video segments, flashing "sale" banners, glitch-style animations
Automated scanning catches a share of these instantly - run a free check - and a manual audit covers the judgement calls a tool cannot make.
Sources
- W3C, Understanding 2.3.1: Three Flashes or Below Threshold - w3.org/WAI
- W3C, How to Meet 2.3.1 (quick reference) - w3.org/WAI/quickref
Last updated . Reviewed by the EqualWeb accessibility team.
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