Accessibility and Text Length: A Practical Guide
Text length is a critical yet often overlooked factor in web accessibility. For screen reader users, overly verbose alt text or vague link labels create significant barriers. This article covers recommended character counts for various accessibility-related text elements.
Recommended Character Counts for Accessibility Text
| Text Element | Recommended Length | Key Point |
|---|---|---|
| Alt text (images) | 80–125 characters | Describe the image content concisely |
| aria-label | Under 50 characters | Briefly describe the interactive element |
| aria-describedby | Under 200 characters | Provide supplementary details |
| Link text | 5–80 characters | Make the destination clear from the text alone |
| Button labels | 2–25 characters | Include an action verb |
| Form labels | 5–60 characters | Specify the expected input clearly |
| Error messages | 30–100 characters | State the cause and how to fix it |
| Page titles | 30–60 characters | Uniquely identify the page content |
| Headings (h1–h6) | 10–70 characters | Accurately summarize the section |
Writing Effective Alt Text
Alt text serves as a replacement for images when they cannot be displayed or when a screen reader is in use. Most screen readers split the reading at around 125 characters, so keeping alt text within 80–125 characters is practical. For decorative images, use an empty alt attribute (alt="") to skip the announcement entirely.
For charts and diagrams, the alt text should provide a summary, while detailed data can be supplied via aria-describedby or in the surrounding text. Avoid prefixes like "image of" or "photo of" — screen readers already announce the element type.
aria-label vs. aria-describedby
aria-label defines the accessible name of an element and should be short and direct — "Open menu," "Search," or "Close" are good examples. When a visible label already exists, prefer aria-labelledby to reference it for consistency.
aria-describedby provides supplementary information, such as password requirements ("At least 8 characters, including letters and symbols"). Keep it under 200 characters and include only what the user needs to complete the action.
Link Text and Button Label Design
Vague link text like "click here" or "learn more" loses context in screen reader link lists. Write descriptive text between 5 and 80 characters that makes sense on its own — for example, "View the 2025 annual report" or "Download the accessibility checklist."
Button labels should include an action verb and stay within 2–25 characters. For icon-only buttons, always provide an aria-label so the action is clear without visual cues.
WCAG Guidelines and Text Requirements
WCAG 2.2 does not prescribe specific character counts, but several success criteria relate directly to text quality. Criterion 1.1.1 (Non-text Content) requires alternative text for all non-text content. Criterion 2.4.4 (Link Purpose) requires that link destinations be determinable from the link text or its context. Criterion 2.4.6 (Headings and Labels) requires that headings and labels describe their topic or purpose.
Conclusion
Designing text with accessibility in mind ensures that information reaches all users accurately. Aim for alt text under 125 characters, aria-labels under 50 characters, and descriptive link text under 80 characters. Use Character Counter to verify your text lengths and keep them within accessible ranges.