Guide

WCAG 2.1 AA in plain language

WCAG is organized around four principles. Content must be Perceivable, Operable, Understandable, and Robust, often abbreviated POUR.

The four principles

• Perceivable. People can sense the content. Images have text alternatives, videos have captions, and text contrast is strong enough to read.
• Operable. People can use every control with a keyboard, have enough time to read, and are not trapped or triggered by flashing content.
• Understandable. Text is readable, pages behave predictably, and forms explain errors clearly.
• Robust. The page works with current assistive technologies and browsers.

The most common failures on public sites

1. Images with missing or meaningless alt text
2. Form fields without visible labels
3. Low-contrast gray text on white or light backgrounds
4. Keyboard focus that disappears or is hidden
5. Links that say only "click here" or "read more"
6. Headings used for styling rather than structure
7. PDFs that are scanned images or have no tags
8. Custom widgets, such as dropdowns and date pickers, that do not work with a keyboard

Ten-minute checks you can run now

• Press Tab repeatedly. Can you see where focus is, and can you reach every control?
• Zoom to 200%. Does the content still fit and remain readable?
• Turn on your operating system's screen reader for one page. Does it read the page in a logical order?
• Check the contrast of body text with a free contrast checker. Aim for 4.5:1 for normal text and 3:1 for large text.
• Install a browser accessibility extension and run it on your homepage and one form.

Automated checks catch only part of the problem. Plan for human testing with assistive technology as well.

General information only. Confirm your obligations with counsel.

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