Accessibility is mandatory in many countries and mostly ignored. Here are the 9 visual accessibility principles that make a site usable for everyone, and legal.
Visual accessibility (part of a11y) is about making interfaces usable for people with visual, motor, neurological and other impairments. The nine golden principles are: use plain text, keep a logical layout, allow keyboard navigation, design for screen readers, use accessible contrast and font size, use proper case, do not rely on color alone, use descriptive actionable elements, and allow zoom. WCAG requires a contrast ratio of at least 4.5:1 for AA and 7:1 for AAA.
Key takeaways
- a11y is short for accessibility (A + 11 letters + Y).
- Screen readers are central: content in images or PDFs is invisible to them, so use plain text.
- Contrast matters: WCAG AA needs 4.5:1, AAA needs 7:1, and never rely on color alone.
- Descriptive links and buttons beat 'click here' for both accessibility and conversion.
- Accessibility is a legal obligation and a business tool: US lawsuits topped 11,000 in 2019.
The 9 golden principles
| Principle | What it means | Priority |
|---|---|---|
| 1. Always use plain text | Keep information in real text and HTML, not baked into images or downloadable files, so screen readers can read it. | Critical |
| 2. Use a logical layout | Respect content hierarchy and heading order (do not jump H1 to H4). Keep related elements close. | Critical |
| 3. Provide keyboard navigation | The whole site must be usable with a keyboard alone, never the mouse only. | Critical |
| 4. Design for screen readers | Use alt text, link titles, semantic HTML5 and ARIA roles for menus, buttons and widgets. | Critical |
| 5. Accessible contrast and font size | Meet WCAG contrast (AA 4.5:1, AAA 7:1) and readable sizes. Color is not enough; size matters too. | Often ignored |
| 6. Use proper case | Avoid all-caps, underlines and capitalized italics; they slow reading, especially for dyslexia. | Common |
| 7. Do not rely on color alone | Color blindness and culture change meaning. Pair color with text or an unambiguous icon. | Critical |
| 8. Use descriptive actionable elements | Links and buttons must say what they do. Avoid vague ‘click here’; it also lifts conversion. | UX + a11y |
| 9. Allow users to zoom | Never block zoom; enlarged content must keep its linear structure. Common offense on mobile. | Common |
Why it is not optional
Accessibility is not extra work or UX debt; it is a tool for richer, more human experiences and more engagement, and it protects you legally. Lawsuits for non-compliance grow every year.
Making interfaces usable for people with visual and related impairments, through plain text, logical structure, keyboard support, contrast, and not relying on color alone.
It is shorthand for accessibility: the letter A, then 11 (the number of letters in between), then Y.
At least 4.5:1 for AA compliance and 7:1 for AAA, for normal text. Large text has a lower threshold.
Color blindness and cultural differences change how color is perceived, so meaning conveyed only by color can be missed. Always add text or a clear icon.
In many countries yes. US accessibility lawsuits topped 11,000 in 2019, and Europe can block non-compliant sites until they meet WCAG AA.
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