Image Alt Text Checker

An alt text checker shows you, image by image, whether a page gives people and search engines a text alternative for its pictures. Paste any page address and our Image Alt Text Checker lists every img tag, image button, image map area and SVG marked as an image, including lazy-loaded images that keep their real address in data-src. Each one is classified: missing alt, empty alt for decorative images, alt that is just a filename or a word like "photo" or "logo", very long alt, alt that repeats the text beside it, and image links left with no accessible name. You get the share of images with good alt text, a filterable table with thumbnails, and a CSV export you can hand to whoever edits the site. Use it to check alt text before a launch, find missing alt tags after a redesign, or audit an online store's product images.

How to use the Alt text checker

1. 1 Paste the page addressEnter the full URL of the page you want to check, such as a product page, a blog post or your home page. Each run checks one page, so test your main templates one by one.
2. 2 Read the summary firstThe top of the result shows how many images were found, the percentage with good alt text, and how many are missing alt or sit inside links with no name. Those two problems matter most for accessibility.
3. 3 Filter the table by problemUse the filter buttons to show only missing alt, filenames and placeholders, decorative images, long alt or images that repeat nearby text. Each row shows a thumbnail, the alt text and why it was flagged.
4. 4 Check the decorative images by eyeAn empty alt is correct for purely decorative images, but a tool cannot tell decoration from content. Look at each thumbnail marked decorative and give real alt text to any that carry information.
5. 5 Export and fixDownload the CSV for your content team or developer, fix the alt text in your CMS or templates, then run the check again to confirm the numbers have improved.

What alt text is and who relies on it

Alt text is the short written description stored in an image's alt attribute, for example alt="Golden retriever puppy asleep on a red blanket". Visitors who can see the picture never notice it. It matters to everyone else: people using screen readers hear the alt text read aloud in place of the image, people on slow connections or with images switched off see it in the empty space, and search engines read it to understand what the picture shows.

Good alt text replaces the image. Ask yourself what a sighted visitor gets from the picture in this particular spot, and write that in a sentence or less. The same photo can need different alt text on different pages: a picture of a chef might be "Head chef Maria plating the tasting menu" on a restaurant's About page and simply alt="" on a recipe page where it is only atmosphere.

A checker can find images with no alt, filenames used as alt and image links with no name. It cannot judge whether a description is accurate or useful. Use the results to find the problems quickly, then have a person who can see the images review the wording.

How to write good alt text, by image type

There is no single formula, but the purpose of the image tells you what to write. These examples cover the image types most sites use. Keep alt text specific, skip phrases like "image of" (screen readers already announce that it is an image), and do not stuff in keywords.

• Product photos: say what the product is and the detail a shopper would want to see, such as color, material or the angle shown. "Women's waterproof hiking boot in brown leather, side view" is far more useful than "boot" or the product SKU.
• Charts and graphs: give the key takeaway in the alt, for example "Bar chart: support tickets fell each month from January to June", and put the actual figures in a table or the text around the chart so everyone can read them.
• Decorative images: dividers, background textures, stock photos used only for mood, and icons next to text that already says the same thing should have an empty alt, written alt="". That tells screen readers to skip them. Do not leave the attribute out, or many screen readers will read the file name instead.
• Logos: name the organization, as in alt="Acme Plumbing". If the logo links to the home page, the alt is the link's name, so "Acme Plumbing home" works well. Words like "logo" on their own say nothing.
• Linked images and image buttons: describe where the link goes or what the button does, not what the picture looks like. A magnifying-glass button needs alt="Search", and a linked banner needs the destination, such as "Shop the winter sale".
• Images of text: if an image contains words, such as a quote graphic or a promotional banner, the alt should contain the same words. Better still, use real text styled with CSS.

What this checker flags, and why

Missing alt is the most serious problem. Without the attribute, assistive technology has nothing to announce, so many screen readers fall back to reading the file name, which might be something like "DSC_0042 dot jpg". This counts as a failure.

An image inside a link or button with no other text is the second failure type. If its alt is missing or empty, the link has no accessible name at all, and a screen reader user hears only "link" or the raw URL. The same goes for input type="image" buttons and clickable image map areas with empty alt.

Filenames and placeholder words are flagged as warnings. Alt such as "IMG_1234", "hero-banner-2", "photo" or "logo" passes a basic automated test because the attribute exists, but it gives the listener nothing. Very long alt over 125 characters is listed as information: that figure is a widely repeated rule of thumb, not a requirement in WCAG, and long descriptions are sometimes justified. Alt that repeats the caption or link text right beside it is also listed as information, because screen reader users hear the same words twice.

Two extra notes help with performance rather than accessibility. Lazy-loaded images that keep their real address in data-src or similar attributes are recognized and counted, and duplicate copies inside noscript tags are skipped. Img tags without width and height attributes are listed as a hint, because those attributes let the browser reserve space and avoid layout shift. CSS can do the same job, and this checker does not read CSS, so treat that hint as something to confirm.

WCAG 1.1.1 and image accessibility

The Web Content Accessibility Guidelines (WCAG), published by the World Wide Web Consortium (W3C), are the standard most accessibility laws and policies point to. Success criterion 1.1.1, Non-text Content, is a Level A requirement, the most basic level. It says all non-text content presented to the user needs a text alternative that serves the equivalent purpose, with exceptions for things like purely decorative images, which should be implemented so that assistive technology can ignore them.

In practice, that means every informative image needs alt text that conveys its meaning, every functional image (a link or button) needs alt text that describes its function, and every decorative image needs an empty alt or an equivalent way of hiding it. Complex images such as detailed charts may need a longer description elsewhere on the page in addition to a short alt.

Automated tools, this one included, can only check part of 1.1.1. They can confirm that an alternative exists and spot obvious placeholders, but whether "Team photo" is an adequate description of a particular picture is a human judgment. A full accessibility review also covers color contrast, keyboard access, headings, forms and much more.

Alt text and SEO: what Google says

Google's own image SEO guidance says it uses alt text, together with computer vision and the content of the page, to understand what an image is about. Descriptive alt text helps your images appear in Google Images and other image results, and alt text on a linked image is treated much like the anchor text of a text link.

The same guidance warns against filling alt attributes with keywords, which it describes as a poor user experience that may cause a site to be seen as spam. Write for the person who cannot see the image, use the words that naturally describe it, and the search value follows.

Context matters too. Google looks at the text around an image, the page title and any caption, so place images near the content they illustrate. Use descriptive file names, such as brown-leather-hiking-boot.jpg rather than IMG_1234.jpg, and make sure important images are in the HTML as img elements rather than only as CSS backgrounds, which search engines do not treat as content images.

The legal context: ADA, EAA and other laws

Accessibility is not only good practice. In the United States, the Americans with Disabilities Act (ADA) has been applied to websites in many lawsuits against businesses, and missing alt text is one of the issues such complaints commonly cite. The Department of Justice has said that businesses open to the public must make their websites accessible, and in 2024 it published a rule under Title II of the ADA that adopts WCAG 2.1 Level AA as the technical standard for state and local government websites, with deadlines phased in by size. Section 508 sets similar requirements for federal agencies.

In the European Union, the European Accessibility Act (EAA) has applied since June 2025 to many consumer-facing products and services, including e-commerce, banking and transport services. Its technical requirements are met through the harmonized standard EN 301 549, which incorporates WCAG success criteria. Canada, the United Kingdom, Australia and many other countries have their own accessibility laws and public sector rules, most of them also referring to WCAG.

Which rules apply depends on where your organization operates, who it serves and what sector it is in. This checker is a practical starting point for one common issue, not a compliance audit or legal advice. If you have obligations under a specific law, have a qualified accessibility professional review your site.

Limits of an automated alt text check

The checker reads the HTML your server sends, the same way most crawlers do. Images inserted later by JavaScript, such as some sliders, galleries and third-party widgets, will not appear in the list. If your site renders mostly in the browser, the image count may be lower than what you see on screen. CSS background images are never included, because they are not content images and cannot carry alt text.

Thumbnails load directly from your site in your browser. Images served over plain http, inline data images and SVG drawn in the page show their address or a placeholder instead of a preview. Very small images marked 1 by 1 pixel are treated as tracking pixels and left out of the count. Each run checks one page; to cover a whole site, run the check on each template, such as the home page, a category page, a product page and a blog post, since most images come from those shared layouts.

Examples you can copy

<!-- Informative: describe what it shows -->
<img src="/img/boot-brown-side.jpg" alt="Women's waterproof hiking boot in brown leather, side view" width="800" height="600">

<!-- Decorative: empty alt, not a missing one -->
<img src="/img/divider-wave.svg" alt="" width="1200" height="40">

<!-- Linked logo: alt names the destination -->
<a href="/"><img src="/img/logo.svg" alt="Acme Plumbing home" width="160" height="40"></a>

<!-- Icon button: alt says what it does -->
<button type="submit"><img src="/img/search.svg" alt="Search" width="20" height="20"></button>

<figure>
  <img src="/img/tickets-2026.png"
       alt="Bar chart: support tickets fell each month from January to June"
       width="900" height="500">
  <figcaption>Monthly support tickets, January to June. Full figures in the table below.</figcaption>
</figure>

<svg role="img" aria-labelledby="cart-title" viewBox="0 0 24 24">
  <title id="cart-title">Shopping cart</title>
  <path d="..."/>
</svg>

<!-- Native lazy loading keeps the real src, with alt as usual -->
<img src="/img/team.jpg" loading="lazy" alt="Our five-person support team in the Denver office" width="1200" height="800">

Common mistakes to avoid

Frequently asked questions