WCAG 2.0 · Level A · Operable
WCAG 2.3.1 — Three Flashes or Below Threshold
Nothing should flash more than three times per second (a seizure risk) above the defined thresholds.
WCAG 2.3.1 at a glance
Level A · Principle: Operable · Added in WCAG 2.0. Level A is the minimum — failing it blocks some users entirely.
What it means
Nothing should flash more than three times per second (a seizure risk) above the defined thresholds.
Who it helps
People with photosensitive epilepsy.
Common failures
- Rapidly flashing animations or video effects
How to meet WCAG 2.3.1
- Avoid rapid flashing
- Keep any flashing under three per second
How to test it
Manual — review animations/video (PEAT tool for analysis).