How to Write Good Alt Text (With Examples)
Practical rules and examples for writing meaningful image alt text for accessibility and SEO.
BLUF
Good alt text describes function and meaning, not just appearance. Write for someone who cannot see the image but still needs the same information.
A simple formula
- Is the image decorative? →
alt="" - Does it link somewhere? → alt describes the destination, not the picture
- Otherwise → short, specific description of what matters
Examples
| Bad | Better |
|---|---|
| "logo" | "AltTagFix home" |
| "chart" | "Bar chart: missing alt issues rose 40% on product pages" |
| "woman smiling" | "Support agent with headset" (only if relevant) |
Length and tone
Aim for one clear sentence; avoid repeating visible caption text. See also WCAG alt requirements.
External resources
Frequently Asked Questions
Should alt duplicate the caption? Usually no—combine information without redundancy.
What about complex infographics? Use short alt plus a longer description nearby or in aria-describedby.
Do icons need alt? Yes when they convey meaning; decorative icons should be hidden from AT.
Can I automate everything? Automation finds issues; humans should approve final copy.