Alt Text Checker

Alt text (alternative text) is a short description placed in an image's alt attribute. It matters for two reasons: it lets screen readers describe images to visually impaired users who cannot see them, and it helps search engines understand and index your images for image search results. Without alt text, an image is invisible to both assistive technology and search crawlers.

The tool scans every <img> tag in your HTML and checks for four things: missing alt attributes, empty (decorative) alt text, suspicious alt text that looks like filenames or generic placeholders, and alt text that passes all quality checks. It also flags images missing a src attribute and reports the line number for each finding.

No. An empty alt="" attribute is the correct way to mark an image as purely decorative. It tells screen readers to skip the image entirely, which is the desired behavior for spacer GIFs, decorative dividers, and images whose meaning is already conveyed by adjacent text. The checker categorizes these as "Decorative" rather than as errors.

Alt text is flagged as suspicious when it exists but appears low-quality. This includes text that simply repeats the filename, uses generic words like "image" or "photo," contains file extensions such as .jpg or .png, starts with camera-generated prefixes like "IMG*" or "DSC*", looks like a random hash, or is either too short (under 4 characters) or too long (over 125 characters). These are common signs that the alt text was auto-generated or copied without thought.

The Alt Text Checker is completely free and runs entirely in your browser. Your HTML is never uploaded, stored, or transmitted to any server. This makes it safe to use with sensitive pages, internal tools, or client work behind logins. No account or API key is required.

Aim for a concise description, typically under 125 characters. The goal is to convey the image's purpose and content in a way that serves someone who cannot see it. If an image contains a lot of information, such as a chart or diagram, consider describing the key takeaway in the alt text and providing a longer description elsewhere on the page. The checker flags alt text that is too long or too short.

Yes. Search engines like Google use alt text to understand what an image depicts, which helps your images appear in image search results and strengthens the overall relevance of your page. Well-written, descriptive alt text that naturally includes relevant keywords improves both accessibility and search visibility. Avoid keyword stuffing, which harms both users and rankings.

Alt text is covered by WCAG 2.1 Success Criterion 1.1.1 Non-text Content (Level A). It requires that all non-text content has a text alternative that serves the equivalent purpose, unless the content is decorative, in which case an empty alt="" is appropriate. Meeting this criterion is a baseline requirement for WCAG conformance and legal accessibility compliance in many jurisdictions.

This tool scans the HTML you paste or upload, so it checks one page or HTML fragment at a time. To audit a full website, paste the HTML of each page individually, or save each page as an .html file and drop them in one at a time. For large multi-page audits, you can export a Markdown report per page and combine them.

It depends on context. If the same image appears multiple times and serves the same purpose, repeating the alt text is acceptable but can be redundant for screen reader users. If an image is repeated purely for layout or branding and the meaning was already conveyed the first time, subsequent copies can use an empty alt="". The checker flags duplicates so you can decide based on the surrounding content.

Yes. The scanner detects whether an aria-label or role="img" attribute is present on each image and includes this information in the findings. However, even when an aria-label is present, WCAG 1.1.1 still requires a proper alt attribute on every <img> tag, so the checker will still flag a missing alt while noting the alternative attribute.

Yes. After scanning, use the Copy report or Download report buttons to export a complete Markdown audit file. The report includes a summary of all statistics plus a detailed breakdown of every image with its line number, status, source, alt text, and any issues found. This is ideal for sharing with your team, attaching to a pull request, or delivering to a client.