WCAG 2.3.1
Three Flashes or Below Threshold
Level AWCAG 2.0
0
automated findings for 2.3.1, across our entire corpus
609 site scans and 941 PDF documents. No engine tests this criterion, ours included, so a site can pass every automated check and still fail it completely.
What it means and how to fix it
For what the criterion formally requires, read the W3C Understanding document.
What this does not measureLimits of these figures, and where the corpus came from
- No automated check on a web page can establish this. It requires a person.
- Not applicable to PDF documents in our checker.
- These are five targeted cohorts, not a random sample of the web. Per-cohort rates are the figure to quote; the pooled rate is a convenience sample.
- Denominators count sites that produced a result. Sites that were blocked or errored are excluded rather than counted as passing.
- Occurrence counts are floors: the engine records at most 25 occurrences of a rule per page.
- The EU and Indian cohorts retained only the primary success criterion per finding, so a rule mapping to several criteria contributes to one of them in those two cohorts and to all of them in the other three.
| Cohort | Scanned | Attempted |
|---|---|---|
| Shopify DTC stores | 75 | 75 |
| US local government | 158 | 221 |
| US healthcare providers | 208 | 218 |
| EU e-commerce | 107 | 170 |
| Indian financial services | 61 | 72 |
Corpus generated 2026-09-18.
Automation cannot check this one
No scan can test WCAG 2.3.1, ours included. A free scan clears the criteria automation can reach, so a manual review can spend its time on this one.
Run a free scan