Free Image Alt Checker
Missing alt text locks search engines and screen readers out of your images — and out of Google Images traffic. NToolHub's free Image Alt Checker scans your HTML and audits every image: missing alt attributes, empty alt, and alt text over 125 characters. A two-minute check that improves both accessibility and image SEO.
How to Use the Image Alt Checker
- Paste the page HTML into the box.
- Click Analyze to audit every <img> tag.
- Add descriptive alt text (under 125 chars) to flagged images.
- Leave alt="" only on purely decorative images.
Features
Paste page HTML to get a per-image table (src, alt text, status), an overall alt-coverage score with progress bar, and categorized warnings for missing, empty and overlong alt text. All parsing happens in your browser.
Benefits & Use Cases
Descriptive alt text feeds Google Images — a major traffic source many sites ignore — and is legally required for accessibility in many jurisdictions. Good alt also gives context when images fail to load.
Tips
Describe what's actually in the image in under 125 characters, include keywords only when natural, and leave alt="" empty solely for purely decorative images. Never stuff keywords into alt text.
Frequently Asked Questions
What is alt text?
The alt attribute describes an image in HTML. Screen readers read it aloud, browsers show it if the image fails, and search engines use it to understand image content.
How long should alt text be?
Keep it under 125 characters — most screen readers cut off longer text. One concise, descriptive sentence is ideal.
When should alt be empty?
Only for purely decorative images (spacers, design flourishes) that add no information. Content images always need descriptive alt.
Does alt text help SEO?
Yes — it's how images rank in Google Images and it reinforces the page's topical relevance. Keyword-stuffed alt, however, can trigger spam filters.
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