Image Alt Text Checker
Paste a page's HTML and this tool lists every img tag it finds, then grades each one's alt text: usable, missing, empty (decorative), or too long. You get a quick summary of how many images need attention. Everything is checked in your browser.
How to check image alt text
- Open the page, view source, and copy the HTML (or just the section with your images).
- Paste it into the box below.
- Read the table and summary, then add or fix alt text on any image flagged as missing or too long.
Examples
A mix of good, missing and decorative images
<img src="/logo.png" alt="Acme company logo"><img src="/chart.png"><img src="/divider.png" alt="">
3 images: 1 with alt text, 1 missing alt, 1 decorative (alt="").
Alt text that is too long
<img src="/hero.jpg" alt="a very long sentence over 125 characters...">
Flagged too-long: shorten the alt text so screen readers stay concise.
Frequently asked questions
Why does image alt text matter for SEO and accessibility?
Alt text is the text alternative for an image, set with the alt attribute on an img tag. For accessibility it is what screen readers announce to people who cannot see the image, and it is shown when an image fails to load, so it is essential for users who rely on assistive technology. For SEO it gives search engines a text description of the picture, which helps the image rank in Google Images and gives the surrounding page extra relevant context. Descriptive, accurate alt text therefore improves both how usable and how findable your pages are.
What counts as good alt text?
Good alt text describes the content and function of the image in a concise sentence, without starting with phrases like "image of" since the screen reader already announces that it is an image. Keep it specific (for example "Golden retriever puppy sleeping in a wicker basket" rather than "dog") and reasonably short. This tool flags alt text longer than about 125 characters as too long, because screen readers read the whole string and very long descriptions become tedious to listen to.
What does an empty alt (alt="") mean?
An empty alt attribute (alt="") marks an image as decorative, telling screen readers to skip it. That is the correct choice for spacers, background flourishes, and icons that sit next to text saying the same thing. This tool counts those separately as decorative rather than flagging them as errors. The real problem is a missing alt attribute entirely, because then assistive technology may read out the file name, which is unhelpful.
What is the difference between a missing alt and an empty alt?
A missing alt means the img tag has no alt attribute at all, so screen readers fall back to reading the file path or nothing useful. An empty alt (alt="") is a deliberate signal that the image is decorative and should be ignored by assistive technology. They look similar but mean opposite things, so this checker reports them as two different statuses: "missing" needs fixing, while "empty" is usually fine.
Does this tool fetch the page or check it live?
No. It only reads the HTML you paste in, so it does not visit the URL or render JavaScript. If your images are inserted by client-side scripts or a lazy-loading library, paste the rendered HTML (for example from your browser's inspector) rather than the raw view-source response so every img tag is included.
Is my HTML kept private?
Yes. The check runs entirely in your browser with JavaScript. Nothing you paste is uploaded, logged or stored anywhere.
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