Demystifying Alt Text: A Comprehensive Guide with Examples

4 minutes read

In the world of web accessibility, few elements are as crucial as alt text. Alt text, short for “alternative text,” is a concise description of an image within an HTML document. It serves a vital purpose: providing information about images to individuals who cannot see them, whether due to visual impairments or because they’re using screen readers or text-only browsers. In this comprehensive guide, we’ll explore the importance of alt text, best practices, and provide code examples and samples to help you get it right.

Why Alt Text Matters

Alt text is a fundamental component of web accessibility for several reasons:

  1. Inclusion: Alt text ensures that everyone, regardless of their abilities or disabilities, can access and understand the content on your website.
  2. Compliance: It’s a legal requirement in many countries, including the United States under the Americans with Disabilities Act (ADA) and Section 508.
  3. SEO Benefits: Search engines rely on alt text to understand and index images, which can boost your site’s search engine ranking.
  4. Usability: Alt text helps all users by providing context for images, such as when images fail to load or if the user is on a slow internet connection.

Best Practices for Writing Alt Text

Writing effective alt text involves striking a balance between providing enough information and being concise. Here are some best practices to keep in mind:

  1. Be Descriptive: Describe the image’s content, function, or purpose. If it’s decorative or doesn’t convey meaningful information, use empty alt text (alt=””) or include a role=”presentation” attribute.
  2. Keep It Concise: Alt text should be brief but descriptive, typically no longer than a sentence or two.
  3. Avoid Repetition: If an image appears multiple times on a page with the same function, use consistent alt text.
  4. Avoid Redundancy: Don’t include phrases like “image of” or “picture of” in your alt text, as screen readers already announce that an image is present.
  5. Include Important Details: If an image contains text, ensure that the alt text conveys this text. Screen readers will read the alt text aloud.

Code Example: Adding Alt Text

Let’s dive into some code examples to see how to add alt text to images in HTML.

<!-- Basic Image with Alt Text -->
<img src="example.jpg" alt="A beautiful sunset over the ocean">

<!-- Decorative Image (Empty Alt Text) -->
<img src="divider.png" alt="">

<!-- Image within a Link (Descriptive Alt Text) -->
<a href="details.html"><img src="product.jpg" alt="Product details page for XYZ Widget"></a>

Alt Text Samples

Here are some real-world examples of alt text for various types of images:

  1. Informative Image: Alt text should convey the image’s content.
    • Image: A chart showing the company’s revenue growth over the past five years.
    • Alt Text: Line chart displaying the company’s revenue growth from 2017 to 2022.
  2. Functional Image: Describe what the image does.
    • Image: A magnifying glass icon for the search button.
    • Alt Text: Search icon – Click to search for products.
  3. Decorative Image: Indicate that the image is purely decorative.
    • Image: A horizontal rule (line) used to separate sections.
    • Alt Text: (Empty alt text or alt=”” or role=”presentation”)
  4. Image with Text: Include the text content of the image.
    • Image: An image containing the phrase “Contact Us.”
    • Alt Text: Contact Us
  5. Complex Image: Describe the main elements or key information.
    • Image: An infographic depicting steps to improve website accessibility.
    • Alt Text: Infographic showing six steps to improve website accessibility.


Alt text is a fundamental aspect of web accessibility that benefits everyone. By following best practices and providing clear and concise alt text for images, you make your website more inclusive and compliant with accessibility standards. Remember that meaningful alt text not only improves accessibility but also enhances SEO and user experience.

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