What is image alt text?

Alt text (alternative text) is an HTML attribute added to img tags that describes the image content. It's read by screen readers for accessibility and by search engines to understand image context.

How does alt text affect SEO?

Alt text helps search engines index your images for Google Image Search, contributes to the overall topical relevance of your page, and can include target keywords naturally.

Should every image have alt text?

Informational images should always have descriptive alt text. Decorative images (backgrounds, spacers) should have an empty alt attribute (alt='') to indicate they can be skipped by screen readers.

How long should alt text be?

Alt text should be concise and descriptive — typically 5–15 words or 50–125 characters. Avoid keyword stuffing; describe what the image actually shows.

Can missing alt text cause accessibility violations?

Yes. Missing alt text on informational images is a WCAG 2.1 Level A violation, which can create legal liability for website owners in many jurisdictions.

On Page Seo

Free

Image ALT Tag Checker

Find images missing alt text, empty alt attributes, and get a full audit of image accessibility and SEO.

Page URL

What is Image ALT Tag Checker?

The Image ALT Tag Checker scans any webpage and audits every image for alt text presence, emptiness, and quality. It identifies images with missing alt attributes, empty alt text, and over-long descriptions — giving you a complete picture of your page's image SEO and accessibility compliance.

Alt text serves two critical purposes: it tells search engines what an image depicts (contributing to image search rankings and page relevance), and it provides a text alternative for visually impaired users relying on screen readers. Both SEO and WCAG 2.1 accessibility guidelines require meaningful alt text on all informational images.

Why Use Image ALT Tag Checker?

Missing alt text is one of the most common on-page SEO errors. It leaves valuable image search ranking opportunities on the table and fails users with visual impairments. A quick alt text audit can uncover dozens of missed optimisation opportunities on a single page.

Key Features of Image ALT Tag Checker

✓Lists all images found on the page with their current alt text
✓Flags images with missing or empty alt attributes
✓Identifies decorative images correctly marked with empty alt (alt='')
✓Shows image src URL for easy identification
✓Counts total images, missing alt count, and compliance rate

How to Use Image ALT Tag Checker

1
Enter the page URL
Paste the full URL of the webpage you want to audit into the input field.
2
Run the audit
Click 'Check Alt Tags'. The tool fetches the page and extracts all img elements.
3
Review the image list
See all images with their current alt text status — missing, empty, or present.
4
Identify missing alt text
Red items indicate images with no alt attribute. Yellow indicates empty alt text.
5
Add optimised alt text
Update images in your CMS with descriptive, keyword-relevant alt text and re-run to confirm.