1.4.10 Reflow

What this criterion requires

Content must reflow to a 320 CSS pixel wide viewport (equivalent to 400% zoom on a 1280px screen) without two-dimensional scrolling, except for content that genuinely needs 2D layout such as maps, data tables and diagrams.

Who it helps

People with low vision who zoom heavily, and every phone user.

Example: fails vs passes

.layout { width: 1200px; }

.layout { max-width: 1200px; width: 100%; }
    @media (max-width: 480px) { .layout { padding: 0 16px; } }

Test at 320px width (400% zoom). Only maps, data tables and diagrams may scroll in two dimensions - inside their own container.

How to meet and fix it

• Build responsively and test at 320px width / 400% zoom
• Let exempt content (tables, maps) scroll inside its own container

Common failures auditors find

• Horizontal scrolling of body text at 400% zoom
• Fixed-width layouts that clip or overlap when zoomed

Automated scanning catches a share of these instantly - run a free check - and a manual audit covers the judgement calls a tool cannot make.

Last updated 12 August 2026. Reviewed by the EqualWeb accessibility team.