What Is Alt Text & Why It Matters for SEO

Do You Know Alt Text?

Alt text (alternative text) is the description of an image on a web page. It makes it easier for visually challenged people to understand what an image intends to mean, enables search engines to know what the theme of the picture is, and is used when an image doesn’t load properly.

(Note: This is not the same thing as an image caption, which appears visibly on the page.)

Most content management systems provide a field for alt text when adding an image, so one need not edit the HTML directly.

You can also use image alt text on social media platforms like Twitter.

Let’s see an example:

Is Alt Text Important?

Alt text plays a crucial role in enhancing the accessibility of images for both users and search engines, even when images cannot be displayed.

Without appropriate alt text, users who rely on screen readers are unable to gather information from images, which unfairly disadvantages individuals with visual impairments. This exclusion can negatively impact your brand’s reputation, website traffic, and conversion rates.

Moreover, ensuring web accessibility also contributes positively to SEO. Search engines like Google utilize alt text to interpret the content of images, leading to a better understanding of your overall content and potentially improving your search rankings.

Alt text is especially beneficial for image SEO, helping images rank higher in Google Images and similar platforms. Such visibility can drive valuable traffic to your website.

For instance, a search for “ragdoll” yields a search engine results page (SERP) that is largely comprised of images, which link back to the respective owners’ websites.

And you can see many of these images use the keyword “ragdoll” or “ragdolls” in their alt text.

Since alt text plays a crucial role in on-page optimization, it is often referred to as “SEO alt text.”

How to Write Alt Text (Key Guidelines)

Discover how to create effective alt text that enhances your website’s accessibility and SEO performance.

Here are three essential guidelines for crafting optimal alt text:

1. Use Alt Text for Appropriate Images Only

Avoid adding alt text for images that serve only decorative purposes (like the one shown below). Such descriptions can create distraction and confusion for users with visual impairments, rather than offering beneficial context. Instead, use a null (empty) alt attribute as follows:
✅<img src=”decorative-image-title.jpg” alt=””>

This signals to screen readers to disregard the image.

Leaving the alt attribute entirely out (as shown below) can lead assistive technologies to announce the image file name instead, resulting in a subpar user experience.
❌<img src=”decorative-image-title.jpg”>

In contrast, always include alt text for images that convey important information:

• Screenshots of social media posts that contain relevant text
• Functionality icons (e.g., shopping cart symbols)
• Photos that supplement textual information (e.g., a smartphone size comparison)
• Charts that present data not otherwise discussed
• Graphics that illustrate processes (e.g., instructions for using chopsticks)

Tip: If you’re using Semrush’s SEO Writing Assistant, the tool will prompt you to include alt text for images. It also offers advice on readability, SEO optimization, originality, and tone of voice.

2. Be Clear and Brief

According to the Web Accessibility Initiative (WAI), alt text should offer “the most succinct description possible of the image’s intent.” The significance of an image varies by context, so remember to consider the surrounding content and audience when crafting alt text.

Take the example of the photo below: the alt text “Woman doing yoga” might suffice in many cases. However, within a fitness guide, a more detailed explanation of the woman’s pose could be essential.

When writing alt text, imagine how you would describe the image during a phone call. Avoid including:

• Photo credits or copyright details—these should go in the caption.
• Redundant phrases like “image of” or “photo of” (unless the format is particularly relevant).
• Information that all your readers should know—this can be added to the caption or main content.
• Information already conveyed through the caption or main content.

Tip: Some suggest limiting alt text to around 125 characters since many assistive technologies cease reading beyond this point. However, this isn’t a strict restriction; if more detail is necessary, refer to the WAI’s guidelines on complex images.

3. Add in a Keyword

The addition of relevant keywords into your alt text will help your images come up in more Google image search results.

To identify which keywords to use, it’s beneficial to perform some keyword research.

Consider utilizing AlphaRank’s keyword research tool for this task. Simply input a keyword that relates to your image and hit “Search.”

The tool will provide keywords that include your original term (or variations of it) along with corresponding keyword difficulty results.

These terms and phrases are excellent options for optimizing your image’s SEO alt text, as long as the image effectively addresses the needs of searchers.

Conclusion

In conclusion, alt text is a vital component of both web accessibility and search engine optimization. By providing descriptive text for images, you not only enhance the user experience for individuals with visual impairments but also improve your website’s visibility in search engine results.

With search engines increasingly prioritizing inclusive design and user-friendly content, incorporating well-crafted alt text can give your site a competitive edge. Remember, every image on your site is an opportunity to communicate with both search engines and users alike.

So, take the time to write meaningful alt text, and watch as your SEO efforts yield better engagement and reach. Prioritizing alt text isn’t just a good practice—it’s an essential strategy for creating a more accessible, SEO-friendly digital environment.