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Image Alt Text Checker

Short answer

Find images missing alt text and check existing alt attributes.

What it does not do: It checks whether alt text is present, empty or a file name, not whether it describes the image well, and images added by scripts or set as CSS backgrounds are not included.

Free · No signup · Runs in your browser
100% in your browser — your content never leaves your device.

What It Does

Scans every <img> on the page and validates alt-text presence, decorative-image flagging via empty `alt=""`, and filename-as-alt patterns (alt text that just repeats the image filename). Returns a list of the images that need attention.

Why It Matters

Alt text is how screen reader users learn what an image shows, and WCAG 1.1.1 requires a text alternative for every meaningful image. Google also uses alt text, together with the page around it, to understand images for Google Images. Missing alt text fails the first group and gives the second less to go on.

How It Works

  1. Enter a page URL or paste its HTML

  2. We read every <img> element and its alt attribute from the HTML

  3. Run quality rules: missing alt, empty alt (decorative), and filename-as-alt

  4. Return alt-text coverage plus a list of the images missing proper alt text

Sample input + output

INPUT
url: https://web.dev/articles/vitals
OUTPUT
images: 9
  with alt: 8
  empty alt (decorative): 1
  missing alt: 0                            OK
  alt = file name: 0                        OK

Coverage: 100%

How to read the result

Images (9 in the sample)
Every <img> element in the HTML your server sends. Images set as CSS backgrounds, drawn with SVG or added later by a script are not counted.
Missing alt (0)
Images with no alt attribute at all. Screen readers then often read out the file name or just say "image", and WCAG 1.1.1 is not met. This is the count that lowers the score.
Empty alt (1)
Images with alt="". That is right for a purely decorative image and wrong for one that carries information. The tool cannot tell which is which, so it shows the number without a verdict — look at each one.
Alt is just the file name
Alt text that repeats the image's file name, such as "hero-banner-2" or "IMG_0423", tells nobody anything. It gets a warning even though the attribute is there.
Coverage (100%)
The share of images that have an alt attribute, empty or not. 100% means nothing is missing; it does not mean every text is good, because the tool cannot judge whether an alt describes its image.
Images to fix
Under the figures, the report lists up to eight images without alt by file name, so you can find them in your template or media library.

Who Uses This

  • E-commerce Manager

    Check product pages for images with no alt text or with the file name as alt text, a common catalogue default.

  • Accessibility Auditor

    Check WCAG 1.1.1 alt-text coverage page by page and list every image without an alt attribute.

  • Content Editor

    Check each page you publish to catch images uploaded without alt text before they pile up.

Common problems and how to fix them

  1. Content images without alt

    Write what the image shows that matters on this page: "Red trail shoe, side view" on a product page, the trend a chart shows in a report. Keep it to a sentence; longer descriptions belong in the text or a caption.

    <img src="/signups.png" alt="Bar chart: sign-ups doubled from March to June">
<img src="/divider.svg" alt="">

  2. The CMS adds images without alt

    Most content systems have an alt field in the media library: make it required for editors and print it in the template instead of leaving the attribute out. For decorative images, have the template write alt="" explicitly.

  3. Icons and logos

    An icon next to a text label is decorative: alt="". An icon that is the only content of a button or link needs alt text naming the action ("Search", "Close menu"). A logo that links home needs the organisation's name, not "logo".

    <a href="/"><img src="/logo.svg" alt="Example Ltd – home"></a>
<button type="button"><img src="/icons/search.svg" alt="Search"></button>
<img src="/icons/check.svg" alt=""> In stock

  4. Alt text stuffed with keywords

    Google's image guidelines warn against filling alt attributes with keywords. Describe the image; mention the topic once, naturally, when it is really in the picture.

  5. Charts and complex images

    Give the alt a short summary, such as "Bar chart: sign-ups doubled from March to June", and put the full figures in the page text or a table next to it, so everyone gets the numbers.

Frequently Asked Questions

When should alt text be empty?
For decorative images that add no informational value (background patterns, dividers). Use `alt=""` so screen readers skip them. Never omit the attribute entirely.
What makes good alt text?
A short phrase that describes what the image shows and why it is there. Skip "image of" or "photo of", and use a keyword only where it genuinely describes the image.
How does Google use alt text?
Google uses alt text, together with the page content, to understand what an image shows, which helps it show the image in Google Images. AI assistants that read a page can use it in the same way.
What about figure captions?
Captions (`<figcaption>`) complement alt text but don't replace it. Both should describe the image; alt is for screen readers, caption is for sighted users.

Sources

The documentation this tool and the explanations on this page are based on.

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