Image Alt Text Checker
Paste HTML to audit all images for missing, empty, or decorative alt attributes. Get an instant accessibility and SEO image report.
Frequently Asked Questions
alt=""), not a missing one. An empty alt tells screen readers and search engines to skip the image. A missing alt attribute is treated differently — screen readers may announce the image filename, which is disruptive for users with visual impairments.alt="" (empty alt) is intentional — it explicitly tells screen readers the image is decorative and should be skipped, and tells Google not to use the image as a content signal. Missing alt (no attribute at all) is ambiguous — screen readers may announce the image filename or source URL, which is disruptive for visually impaired users. Google may attempt to infer context from the surrounding page. For decorative images (spacers, background patterns, purely aesthetic graphics), always use alt="" — the empty attribute. Only use a descriptive alt text when the image conveys information that is not available in the surrounding text.alt attribute is essential — it provides the text alternative for an image when it cannot be displayed (slow connection, image error) or when accessed by screen readers or search engine crawlers. It is required by accessibility standards. The title attribute on an img element creates a browser tooltip on hover — it is optional and has no meaningful SEO value. Many screen readers ignore the title attribute or treat it inconsistently. Do not confuse alt with title: alt is accessibility-critical, title is decorative. Focus your optimization effort on alt text only.red-apple-white-plate.jpg not IMG_2048.jpg; Surrounding text — the caption and nearby paragraph content; Page topic and title — the overall relevance of the page the image is on; Structured data — ImageObject schema markup provides additional metadata; Computer vision — Google increasingly uses AI to understand image content directly; Page speed — properly sized, compressed images (WebP format) improve Core Web Vitals which is a ranking signal. All signals work together — a great alt text on a slow-loading image on a thin-content page still won't rank well.background-image: url(…)) cannot have alt text because they are not HTML elements. This is intentional: CSS background images are considered decorative by design. Screen readers do not announce CSS backgrounds, and Google does not associate them with content the same way it does <img> elements. If an image is informational (a product photo, chart, infographic, diagram), it should be in HTML as an <img> tag with alt text, not as a CSS background. Only use CSS background images for truly decorative visuals — textures, patterns, and design elements that do not convey meaningful information.About This Image Alt Checker
This free image alt text checker fetches any public URL and lists all images found on the page, flagging those missing the alt attribute or with an empty alt="". Results include each image's source URL for easy identification.
Missing or empty alt attributes hurt both SEO (image context is lost to crawlers) and accessibility (screen readers cannot describe the image). WCAG 2.1 Success Criterion 1.1.1 requires meaningful alt text for all informative images.
When to use this tool
- Auditing a page for WCAG 2.1 accessibility compliance
- Identifying images that are invisible to search engine crawlers
- Checking CMS-generated pages for missing alt text
- Pre-launch accessibility and SEO review
Standards & References
How It Works
Paste HTML
Paste the full HTML source of any web page. The tool works entirely in your browser — no HTML is sent to any server.
DOM Parsing
JavaScript parses the HTML and queries all img elements, checking each for the presence and value of the alt attribute.
Categorized Report
Images are split into three groups: missing alt (needs fixing), empty alt (decorative, intentional), and has alt text (good). A summary score is displayed.
Common Use Cases
Technical SEO Audit
Check every page for missing or empty alt tags as part of a comprehensive technical SEO audit to improve image search visibility and page quality.
Accessibility Compliance
WCAG 2.1 requires meaningful images to have descriptive alt text. Use this tool to identify violations before accessibility audits or legal reviews.
Image SEO Optimization
Find all images with generic filenames used as alt text (e.g., img-2023.jpg) and replace them with descriptive text to improve Google Image Search rankings.
Content Migration Review
Before migrating content between CMS platforms, audit all images to ensure alt text transfers correctly and no images are stripped of their attributes.
E-commerce Product Pages
Audit product image alt text to ensure every product image is optimized with descriptive, keyword-rich alt text for better visibility in Google Shopping.
Blog Post Review
Before publishing a blog post, paste the HTML to ensure every hero image, infographic, and inline image has appropriate alt text for screen readers and search engines.
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alt="" vs No Alt Attribute: Why This Tiny Difference Means "Skip This" or "Announce the Filename"
alt="" and a missing alt attribute look nearly identical in your HTML editor — one extra empty-quotes substring — but to a screen reader, they mean opposite things: alt="" says "decorative, skip this," while missing alt often triggers an announcement of the filename itself. Here's the practical difference, why every img tag should have an alt attribute (even if empty), and the special case where alt="" on an image-as-link removes the link's accessible name entirely.
Alt Text and the Law: How WCAG 1.1.1 Became Central to ADA Lawsuits and the European Accessibility Act
Missing alt text has become a commonly-cited basis for ADA website accessibility lawsuits in the US, with thousands filed annually affecting businesses of all sizes — and the EU's European Accessibility Act adds direct legislative requirements referencing the same WCAG standards. Here's how alt text fits into WCAG 1.1.1, the empty-vs-missing alt attribute distinction that audits often miss, and why good SEO alt text practices overlap substantially with legal compliance.
Image SEO Beyond Alt Text: File Naming, WebP/AVIF, Schema, and Image Sitemaps
Google Images accounts for 22% of all web searches and most sites ignore its ranking signals entirely. Here's how image file naming, WebP/AVIF formats and Core Web Vitals, lazy loading and Googlebot, ImageObject schema, and image sitemaps all contribute to image search visibility.
Writing Alt Text That Works for Both SEO and Accessibility
Alt text that works for both screen readers and SEO follows specific principles: contextual relevance, appropriate keyword inclusion without stuffing, and different approaches for different image types. Here's the craft behind writing alt text that does both jobs well.
Image Alt Checker — Find Every Missing Alt Text on Any Web Page
Learn what image alt text does for SEO and accessibility, what good alt text looks like, and how to use a free image alt checker to find all missing or inadequate alt text on any web page.
