Alt Text Generator

Alt text (alternative text) is a written description of an image that appears in HTML code, serving two critical purposes: accessibility and search engine optimization. Screen readers used by visually impaired users rely on alt text to describe images, making your website accessible to everyone. Search engines like Google cannot see images the way humans do — they read alt text to understand image content and context, which directly influences image search rankings and overall page relevance. Good alt text is descriptive, concise (under 125 characters), avoids phrases like "image of" or "picture of," and includes relevant keywords naturally. This tool helps you write and evaluate alt text by scoring it against a 7-point checklist covering length, descriptiveness, keyword inclusion, and accessibility best practices. Upload an image to see it alongside your alt text, making it easy to write accurate descriptions. The entire process runs in your browser — your images are displayed locally using FileReader and never uploaded to any server.

The scoring algorithm evaluates your alt text against established web accessibility guidelines (WCAG 2.1) and SEO best practices using pure JavaScript string analysis. It checks seven criteria: character length (penalizing both too-short descriptions under 20 characters and too-long ones over 125 characters), presence of filler phrases like "image of" or "photo of" that waste character space, use of file name patterns (like IMG_0234) that indicate a copy-paste mistake, keyword density to ensure relevant terms are included naturally, sentence structure for readability, avoidance of redundant information, and overall descriptive quality based on word variety. Each criterion is scored individually, and a weighted average produces the final score from 0 to 100. The tool also provides specific suggestions for improvement — for example, if your alt text starts with "image of," it recommends removing that prefix. Image preview uses the FileReader API to display the image locally in the browser canvas, and no image data or alt text content is ever transmitted to any external server.