What Is Alt Text? Definition and Examples
Descriptive text for images in the HTML code that explains the image content to search engines and screen readers.
What is alt text?
Alt text (alternative text) is an HTML attribute that describes the content of an image in words. It is displayed when an image cannot load, and screen readers read it aloud for visually impaired users.
Example: a bakery shows a photo of a braided loaf on its product page. Instead of alt="image1", the image tag reads alt="Braided butter loaf on a wooden board". A screen reader user hears what the photo shows, and Google can file the image under the right topic.
Why does alt text matter for SEO?
Search engines cannot "see" images directly. Alt text is therefore key for Google to understand what an image shows and to index it correctly in image search. Well-optimized alt text improves:
- Image search rankings – Google uses alt text as a primary signal for image search
- Accessibility – screen readers read alt text aloud
- Context – it helps search engines place the content of the page more accurately
The same descriptions help AI systems that process images and text together. Our article on multimodal AI optimization explains how.
Best practices
Good alt text is descriptive, precise and natural. Avoid keyword stuffing. Describe what is actually visible in the image, and include the target keyword only when it fits the content.
Frequently asked questions
What is alt text?
Alt text is an HTML attribute that describes the content of an image in words. It appears when an image cannot load, and screen readers read it aloud.
Why does alt text matter for SEO?
Search engines cannot see images directly. Google uses alt text as a primary signal for image search, and it helps search engines understand the content of the page.
What is an example of alt text?
On a bakery's product page, a photo of a braided loaf gets alt="Braided butter loaf on a wooden board" instead of alt="image1".
How do I write good alt text?
Describe what is actually visible in the image, precisely and naturally. Avoid keyword stuffing and include the target keyword only when it fits.