Published November 4, 2026

WCAG 1.4.10 Reflow, Level AA

Does WCAG require content to reflow at 320 CSS pixels?

Yes at Level AA. Success criterion 1.4.10 Reflow requires that content can be presented without loss of information or functionality, and without requiring scrolling in two dimensions, for vertical scrolling content at a width equivalent to 320 CSS pixels. Note 1 in the criterion equates that width to a 1280 CSS pixel viewport at 400% zoom. The text is in the W3C WCAG 2.2 Recommendation.

What does reflow require at 320 CSS pixels?

Content that normally scrolls vertically must fit a 320 CSS pixel wide view without forcing the reader to scroll left and right to read a line of text or reach a control. Horizontal scrolling content has the matching height check at 256 CSS pixels. The W3C explanation is in Understanding Success Criterion 1.4.10. Responsive layouts that stack into one column are a common way to meet it when content and controls stay available. Locking the page to one device orientation is a separate failure under orientation.

How is reflow different from resize text?

1.4.4 Resize Text is Level AA and checks that text can reach 200% without loss of content or functionality. 1.4.10 is a separate Level AA criterion about layout width, not font size alone. A page can pass 200% text resize and still fail reflow if lines run off the side at 320 CSS pixels. The full answer for 200% is on the resize text page. Surviving a user’s larger line and letter spacing is a third check, on the text spacing page. Which version added 1.4.10 is on the WCAG 2.1 vs 2.2 page.

What content may still scroll in two directions?

Parts that need a two-dimensional layout for use or meaning. The criterion notes list images needed for understanding such as maps and diagrams, plus video, games, presentations, data tables, and interfaces where a toolbar must stay in view while someone works. The rest of the page still has to reflow. Target size is measured in CSS pixels and does not change with zoom, which is a different rule on the target size page. Sticky chrome that covers the focused control is covered on the focus not obscured page.

Does the Title II web rule include reflow?

Yes. The Department of Justice rule for state and local government websites names WCAG 2.1 Level AA. That level includes 1.4.10 at Level AA. Governments with a population of 50,000 or more have until April 26, 2027. Smaller governments and special districts have until April 26, 2028. Who must comply is on the Title II web rule page. A scanner can flag fixed widths or overflow. It often cannot tell that a control disappeared after the layout stacked. A person checks that, which is why a passing score is not conformance, as covered on the scanner page. The fix belongs in the layout templates, which is remediation.