SEO Term Definition
Alt Text
Alt text (alternative text) is an HTML attribute added to image tags that describes the image for screen readers, accessibility tools, and search engine crawlers.
Reviewed by Alexander Yarovenko · Updated: 2026-06-22
What is Alt Text?
Alt text is the alt attribute of an HTML <img> tag. It provides a text description of the image content, which is displayed when the image fails to load and read aloud by screen readers.
<img src="ctr-chart.png" alt="Bar chart showing CTR by SERP position for informational queries">Why Alt Text Matters for SEO
- Google cannot reliably "see" images — alt text is how it understands image content
- Images with descriptive alt text can rank in Google Images and Image Search
- Improves accessibility, which is a quality signal for rankings
- Provides anchor text context for the surrounding page topic
How to Write Good Alt Text
- Be specific and descriptive: describe what the image shows, not what you want it to rank for
- Keep it under 125 characters
- Include keywords naturally where relevant — never stuff keywords
- Don't start with "image of" or "photo of" — Google already knows it's an image
- Leave alt empty (
alt="") for purely decorative images