WCAG 2.2 success criterion 1.4.10, Reflow, is a Level AA requirement: content reflows at 320 CSS pixels without horizontal scrolling.
Read the criterion in the W3C Recommendation, WCAG 2.2 (opens in a new tab).
How BearScan checks it
Content reflows at 320 CSS pixels without horizontal scrolling
Checked automatically: loads the page in a browser. Severity: high. A low-vision user zoomed to 400% sees a 320-pixel viewport. If the page does not reflow, every line has to be scrolled sideways to read.
An approximation: The rendered page is resized to 320 CSS pixels wide and measured: the document's width, and every element that extends past the edge outside a scroll container of its own. Overflow caused only by tables, maps, video, code or diagrams is reported for review, since the criterion lets those scroll in two dimensions. A page that decides its layout only at load, not on resize, is measured as it stands.
How to fix it. Use a responsive layout that collapses to a single column at 320 CSS pixels. Avoid fixed widths, and let tables, maps and code blocks scroll on their own rather than the whole page.
All WCAG 2.2 criteria · Next: 1.4.11 Non-text Contrast
Questions
Is WCAG 1.4.10 required by the ADA?
The ADA doesn't name a technical standard for businesses, but the Justice Department's 2022 guidance points businesses to WCAG, and its 2024 rule for state and local governments adopted WCAG 2.1 Level AA, which includes 1.4.10.
Can an automated tool check WCAG 1.4.10?
Mostly. BearScan checks it automatically (loads the page in a browser). A clean result still isn't proof every page passes, only the pages scanned.
How do I fix a WCAG 1.4.10 failure?
Use a responsive layout that collapses to a single column at 320 CSS pixels. Avoid fixed widths, and let tables, maps and code blocks scroll on their own rather than the whole page.