Two-Dimensional Scrolling Required

Content should be readable without scrolling in two directions, so users who zoom or enlarge text don't have to pan horizontally on every line.

WCAG Reference

Maps to: WCAG 1.4.10 Reflow | Applies to: WCAG 2.1, WCAG 2.2 Introduced in: WCAG 2.1 | Level: AA | Read the official specification →

What this rule checks

This is a screen-level rule detecting content that requires scrolling in two directions to be read. It looks for:

1. Scroll views — a scroll view that scrolls horizontally while nested inside another scrollable area, or that is wider than the screen. A text view in this state is reported as a warning rather than a violation.
2. Tables and collection views — a cell whose content scrolls horizontally inside a vertically scrolling table, or a collection view that scrolls horizontally at any depth.
3. Web views — a web view that scrolls horizontally.
4. Element overflow — any element whose right edge extends past the screen, attributed to the scrollable area that contains it; if there is none, the overflowing element itself is flagged.

Findings are deduplicated: once an element or one of its ancestors has been flagged, its descendants are not reported again. Legitimate horizontal scrolling is exempted through a set of recognized patterns: paging controls with a page indicator, step indicators, chip and filter bars, date pickers, image carousels, data tables, maps, and any element identified as a map, diagram, carousel, gallery, floor plan, or canvas.

Why it matters

WCAG 1.4.10 requires content to be presentable without scrolling in two dimensions, because a user who has enlarged text or zoomed in must otherwise pan horizontally to read every single line. Reading a paragraph becomes a sequence of scroll-right, read, scroll-left-all-the-way, scroll-down operations, for each line. This is the difference between reading a screen and giving up on it. The criterion exempts content that genuinely requires two dimensions, such as maps and data tables, which is what the exemption patterns above encode.

Common failure patterns

• a fixed-width layout inside a vertical scroll view that overflows once the text is scaled up
• horizontally scrolling content nested inside a vertically scrolling parent, where neither direction can be avoided
• web content rendered at a fixed viewport width
• cells whose content overflows the screen edge at larger Dynamic Type sizes

Remediation guidance

• let text wrap rather than extend — use flexible widths and allow the container to grow vertically
• where content must be wide (a data table, a chart), keep it in a container that scrolls horizontally on its own while the surrounding page scrolls only vertically, and confirm the container matches one of the exemption patterns, or is genuinely exempt under 1.4.10
• test at the largest Dynamic Type size and confirm no element's right edge crosses the screen boundary
• avoid nesting a horizontal scroll view inside a vertical one unless the inner view is a carousel or paging control

Related docs

• iOS Rule Repository
• Accessibility Issue Remediation Guide