Check if your images have proper alt text for accessibility and SEO. Get AI-powered suggestions to improve your descriptions.
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An alt text checker is a tool that evaluates the quality and accessibility compliance of image alternative text (alt attributes) on a web page. It analyzes whether alt text is present, descriptive enough, the right length (under 125 characters), free of common mistakes like keyword stuffing or filename usage, and compliant with WCAG 2.2 Success Criterion 1.1.1 (Non-text Content). Alt Audit's free checker scores your alt text on a 0–100 scale and provides specific, actionable feedback to improve both accessibility and SEO performance. According to the WebAIM Million 2025 study, missing alt text is the #1 most common accessibility error found on the web, affecting 58% of the top 1 million websites.
Follow these guidelines for accessible, SEO-friendly image descriptions.
Be specific and descriptive
"Golden retriever puppy playing with red ball in sunny backyard"
Keep it concise (125 characters or less)
Screen readers may cut off longer descriptions
Describe the image content, not its purpose
Focus on what's in the image, not why it's there
Include relevant keywords naturally
Helps with image SEO when done appropriately
Don't start with "Image of" or "Picture of"
Screen readers already announce it's an image
Don't use the filename
"IMG_2847.jpg" tells users nothing
Don't keyword stuff
"Dog puppy pet animal canine golden retriever dog"
Don't leave it empty (for meaningful images)
Empty alt text should only be used for decorative images
See the difference between bad and good alt text
"product.jpg"
"Blue wireless headphones with cushioned ear pads on white background"
"Image of a team"
"Five marketing team members collaborating around laptop in modern office"
"" (empty)
"Chart showing 45% increase in organic traffic over 6 months"
There are several ways to check. You can right-click an image in your browser and select "Inspect" to see the HTML alt attribute. You can view the page source (Ctrl+U) and search for "alt=". You can use browser extensions like WAVE to highlight missing alt text visually. Or you can use Alt Audit's free checker on this page to analyze individual alt text quality, or our WordPress plugin to scan your entire media library in bulk.
Aim for 80 or above on the 0–100 scale. A score of 80+ means your alt text is descriptive, the right length (under 125 characters), free of common mistakes, and likely to be helpful for both screen reader users and search engines. Scores between 50–79 indicate room for improvement, while below 50 suggests significant issues like missing descriptions, filename usage, or keyword stuffing.
Meaningful images — product photos, infographics, charts, screenshots, team photos — must have descriptive alt text per WCAG 2.2. Decorative images (borders, spacers, background patterns) should have empty alt text (alt="") to tell screen readers to skip them. The key distinction: if removing the image would lose information, it needs alt text. If it's purely visual decoration, use empty alt.
Keep alt text under 125 characters. Most screen readers (JAWS, NVDA, VoiceOver) truncate alt text at approximately 125 characters, so anything beyond that may not be read to the user. The ideal range is 50–125 characters — long enough to be descriptive, short enough to be concise. For complex images like charts or infographics that need longer descriptions, use the longdesc attribute or a visible caption instead.
Yes. Alt text is a confirmed ranking factor for Google Image Search and provides contextual signals for web search rankings. Google uses alt text to understand image content and how it relates to page topics. Pages with optimized image alt text receive up to 40% more traffic from Google Images according to Ahrefs research. Alt text also helps your images appear in Google's image packs and visual search results.
Yes — AI-generated alt text is effective when the AI produces accurate, descriptive text. Alt Audit uses Google Gemini AI to analyze actual image content and surrounding page context, generating specific descriptions rather than generic ones. The key is accuracy: always review AI-generated alt text before publishing. Alt Audit's WordPress plugin lets you preview and edit every description before applying it to your media library.
Founder & Web Accessibility Specialist, Full-Stack Laravel & WordPress Developer
Rustamjon built Alt Audit to automate the tedious process of writing alt text for hundreds of images. The free checker tool uses the same quality scoring engine that powers the full platform — helping anyone improve their image accessibility without signing up.
Connect on LinkedInOur WordPress plugin scans your entire media library and generates AI alt text in bulk. Start with 25 free credits.