What Is Alt Text?

Alt text, which is short for alternative text for images, is very important for accessibility, and can also have benefits for SEO. Briefly, alt text is wording that is added to an image to describe it to search engines. It also allows people using screen readers to be able to know what the image is without actually being able to see it.

Here’s a quick three-minute explainer on alt text from Google:

What Are Some Best Practices for Writing Alt Text?

Google’s Search Advocate John Mueller has said that Google has no specific guidelines regarding alt text. This came up during a recent Google SEO office hours hangout , when Muller dispelled speculation that Google only crawls the first 16 words of an alt text tag.

Mueller said that there are actually no restrictions for how long your alt text can be, and that in terms of SEO, you can add a lot of wording to an alt text tag as long as it's relevant for that particular image.

Here’s a helpful example from Mueller of what kind of relevant text can improve your alt text:

If you have a picture of a beach, you could use an alt text and say, ‘Oh this is a beach.’ But you could also say, ‘this is the beach in front of our hotel or this is the beach that we took a photo of when we were doing a chemical cleanup.’ And kind of those intents are very different and people would be searching in different ways in Google Images to find more information there. And giving that extra context always makes sense, in my opinion.”

While this guidance from Google may seem vague, it’s safe to say that any effort to describe an image with helpful context is better than nothing. However, Google does clearly mention in its best practices for images documentation that you should not stuff keywords into your alt text tags . This means you should not use the alt text field as an opportunity to mindlessly input your desired search phrases, or even the name of your company , with no context.

Here’s an example from Google of keyword stuffing in the alt text attribute:

How Does Alt Text Impact My Search Ranking?

The impact of alt text on your search rankings is, like most things related to SEO, a bit hard to determine. While Google hasn’t directly mentioned alt text as an official search ranking factor, it has given several clues to its importance. For example, their guidelines do state that keyword stuffing alt text attributes like mentioned above could cause your site to be marked as spam and negatively impact your site’s search rankings.

In 2020, Mueller gave another nugget of insight into alt text’s impact on SEO . He said the alt text attribute is particularly important for image search, and that “using the alt attribute is a good way to tell us this is on that image and we’ll get extra information from around your page with regard to how we can rank that landing page.”

So the quick answer is yes, alt text is an important part of your holistic SEO strategy.

While making sure that every image on your site has appropriate alt text will not be a quick fix to better performance on search, it is an important part of your site’s usability and overall SEO strategy. Plus, when done correctly and with appropriate context, it’s another chance to reinforce your content’s search phrase for Google’s crawler.