Image Alt Text Checker
Alt text describes an image for people who cannot see it and for search engines that index images. This checker lists every image on a page with its alt text and a verdict: missing alt attributes, empty alt text on images that are the only content of a link, alt text that is just a file name, phrases like “image of”, descriptions that are too long and the same text repeated on many images. Decorative images with alt="" are recognised as correct.
- Encrypted connection
- No sign-up
- Free to use
How to use Image Alt Text Checker
- Enter a page URL (or paste its HTML).
- Click “Check alt text”.
- Start with the images marked red.
- Write a short description of what each image shows.
Image Alt Text Checker features
Missing alt
Images without the attribute.
Linked images
Empty alt where the image is the link.
Quality checks
File names, “image of”, length, repeats.
Decorative images
alt="" recognised as intended.
Image buttons and maps
input type=image and area elements.
Paste mode
Analyse HTML you paste, e.g. a staging page.
When to use Image Alt Text Checker
- Accessibility reviews against WCAG 1.1.1.
- Improving image search visibility.
- Checking CMS uploads that use file names as alt text.
- Reviewing product pages before launch.
Image Alt Text Checker FAQ
What is good alt text?
A short sentence that says what the image shows or does in this context, for example “Red road bike leaning on a wall”. Leave out “image of” – screen readers already say it is an image.
When should alt be empty?
When an image is purely decorative and adds no information. Use alt="" so screen readers skip it; leaving the attribute out makes some read the file name.
How long can alt text be?
There is no hard limit, but about 125 characters is a common guideline. Put longer explanations in a caption or the surrounding text.
Does alt text help SEO?
Yes. Search engines use it to understand images and the page, and it is the anchor text when an image is a link.
Alt text for people and search engines
Screen-reader users hear alt text in place of an image. Without it they may hear a meaningless file name, or nothing at all on a linked image, which leaves them guessing where the link goes. That is why missing alt text is one of the most common accessibility failures found in audits.
Search engines read alt text too, especially for image search, where it is one of the main signals besides the file name and the surrounding text. Descriptive, honest alt text helps both audiences; stuffing it with keywords helps neither.
The checker reads the HTML of the page, so images added later by JavaScript are not included.
Privacy: the address you enter is fetched by our server only to run this check. The downloaded HTML is passed to your browser for analysis and is not stored, and the results are not saved on our side. Requests are rate-limited to keep the service fair for everyone, so if you check many pages in a row you may need to wait a few minutes.
Limits: pages are read up to 2 MB of HTML, redirects are followed up to eight hops and each request has a short timeout. Pages behind a login, servers that block automated requests and content added only by JavaScript cannot be analysed this way; for those, copy the page source from your browser and use the paste option where it is available.
Tip: fix the problems marked red first, because they matter most. Yellow warnings are worth reviewing but are often harmless in context, and blue notes are information. After a change, run the check again to confirm the result – search engines pick up the change on their next visit to the page.