Alt text, or alternative text, is a critical component of web content that helps ensure images are accessible to all users. It’s especially crucial for individuals with visual impairments, as it allows them to understand what images convey through screen readers.
But alt text isn’t just for accessibility—it’s also a key element in optimizing your website for search engines. Writing effective alt text can improve your SEO rankings, making your content more discoverable.
In this article, we’ll explore how to craft alt text that benefits both accessibility and SEO, while following best practices to ensure clarity and relevance.
What is Alt Text?
Alt text is a descriptive attribute used to describe the content and function of an image on a webpage. When a user with visual impairments accesses a webpage, their screen reader will read the alt text aloud, helping them understand the context of the image.
Alt text also serves as a fallback if an image fails to load properly. By providing a text alternative, you ensure that the image’s meaning and purpose are communicated effectively. It’s essential to follow best practices when writing alt text to make it both informative and beneficial for SEO.
Why Alt Text Matters for Accessibility
Writing alt text is fundamental for web accessibility. According to accessibility standards such as the Web Content Accessibility Guidelines (WCAG), alt text is required for any image that serves a functional purpose. Without alt text, visually impaired users may struggle to comprehend the purpose of images, which can hinder their browsing experience.
For example, a visually impaired user who is trying to shop online might not understand what a product looks like without an accurate alt description. Alt text also ensures compliance with accessibility laws in many countries, such as Section 508 in the United States.
Alt Text for SEO: Why You Need It
Alt text is not just for accessibility—it also plays a significant role in SEO. Search engines like Google can’t “see” images the way humans can, but they rely on alt text to understand what an image is about. Well-written alt text can help your images rank higher in search engine results, improving your overall SEO.
When you include relevant keywords in your alt text, you provide search engines with more information about your content, which can increase your chances of being found in image search results. Additionally, using descriptive alt text can enhance your page’s relevance, driving more traffic to your site.
How to Write Effective Alt Text
When writing alt text, it’s crucial to balance clarity, brevity, and relevance. Here are some tips to guide you:
Keep it Short and Descriptive
Alt text should be concise but descriptive. Aim for a length of 125 characters or fewer, as screen readers may cut off longer descriptions. Focus on the image’s purpose and the key details that convey its message. For example, instead of saying “a photo of a person,” describe the person’s action or emotion: “a person smiling while holding a birthday cake.”
Be Specific and Contextual
The purpose of alt text is to communicate the image’s meaning in context. What does the image represent in relation to the surrounding content? If you have an image of a product, describe its key features or what it is used for. If the image is a logo, include the company name. Providing context helps users and search engines understand the image’s relevance to the content on the page.
Avoid Redundancy
Don’t use phrases like “image of” or “picture of” in your alt text, as these are already implied. Instead, directly describe what the image is showing. For example, instead of “image of a dog running,” just say “a dog running in a field.”
When to Use Empty Alt Text
Not all images require alt text. Decorative images, such as background images or non-informative visuals, do not need detailed alt text. For these types of images, use an empty alt attribute (alt=””). This ensures screen readers skip over these images, providing a smoother browsing experience for users who rely on assistive technology. For example, a decorative border or a background texture doesn’t need alt text because it does not contribute to the overall content.
How to Write Alt Text for Specific Image Types
Certain image types require more tailored alt text descriptions. Let’s look at how to handle some of the most common types:
Product Images
For e-commerce websites, product images should include detailed descriptions of the product, including its color, size, and any other key features. For example, “red leather handbag with gold clasp and adjustable strap.”
Logos
When describing logos, use alt text to provide the name of the organization or brand. For example, “Apple logo in white.”
Infographics
Infographics can be complex, so it’s essential to summarize the key data points in the alt text. If the infographic is too detailed, provide a general description in the alt text and link to a more detailed explanation or provide a longer description elsewhere on the page.
Icons and Buttons
Icons and buttons typically serve a functional purpose, so your alt text should describe what action the user can take. For example, for a shopping cart icon, use “add item to shopping cart.”
Best Practices for Alt Text Optimization
Here are some best practices to optimize your alt text for both accessibility and SEO:
- Use Relevant Keywords: Including relevant keywords in your alt text helps search engines understand the content of the image. However, avoid keyword stuffing, as this can lead to a poor user experience and may harm your rankings.
- Keep it Natural: Write alt text that reads naturally. It should be easy to understand and reflect the image’s context.
- Be Specific: When possible, be specific about what the image shows and its relevance to the page. A more detailed description will benefit both accessibility and SEO.
Conclusion
Writing effective alt text is essential for both accessibility and SEO. By crafting concise, relevant, and descriptive alt text for your images, you ensure that your website is accessible to all users, regardless of their abilities. Additionally, alt text helps search engines better understand the content of your images, which can improve your site’s visibility and ranking. Follow these best practices to create alt text that enhances your website’s user experience and SEO performance.