At a Google Office-hours meetup, Google’s John Mueller answered a question about how to use alt text for SEO. In the process, he eliminated the idea of a 16-word limit for alt text and suggested ways to use alt text, which is good for SEO.
alt text
Alternative text is a reference to the image’s alternative text. The purpose of image alt text is to describe what is in the image for someone visiting the web page with a screen reader.
A screen reader is an assistive device that helps visually impaired people access web documents and more.
Screen readers read computer documents aloud so that those who access the document can hear what is written.
Screenshot of Google’s John Mueller
Does Google read more than 16 words in image alt text?
John summarizes a question submitted to him.
He said it was from a food blogger:
“Google says you can use up to 16 words in alt text.
The question is, did Google read the rest of my alt text and what does that mean for usability? “
Mueller answered this question:
“And I think the important part here is that we don’t have any guidelines on the length of the alt text.
So, from a Google search perspective, you can add a lot to the alt text of an image if it’s relevant to a particular image. “
16 word alt text limit?
The person who asked the question mentioned Google’s limit of 16 words they thought could be used in alt text.
The source of this idea may come from an SEO test that tries to identify text in images alt text is searchable in Google Images.
The test used non-existent words (basically gibberish) and found that Google couldn’t search for images by using more than 16 words.
Testing Google with gibberish tends to lead to flawed “SEO test” results.
The reason that using gibberish is a flawed approach is because Google aims to rank actual words, not gibberish.
So for gibberish, Google will most likely pull the regular algorithm (because it doesn’t apply) and simply try to do a direct match from the query to the web page, which is not how Google search usually works.
Whether the bug has an impact on SEO testing is an open question.
The point is that the 16-character limit is not imposed by Google, but determined based on the results of SEO testing.
Mueller explains how to replace text with images
Mueller went on to explain how Google uses alt text in images and what it means for SEO.
Mueller continued his answer:
“When it comes to alt text, we mostly use it to better understand images.
So if someone is… searching Google Images for something that matches alt text, then we can use that to understand that your image is related to the alt text on that particular page.
This is the main use case for alt text.
We also use alt text as part of the page. But for me it’s usually something already visible on the page.
So it’s not a very important thing to the page itself.
So I’d really use it as something that applies to images, and I’d use it to improve usability and give Google Images a better understanding of that particular image. “
what word to use in alt text
Next, Mueller sets out to explain how to choose the best words for image alt text.
Mueller continued:
“And I think it’s probably also worth mentioning that when it comes to Google Images, you don’t necessarily need to describe exactly what’s in the image.
But rather, it’s kind of like what this image means to your particular page.
So if you have a picture of a beach, you can use 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 we photographed during a chemical cleanup.
The kinds of these intents are very different, and people search Google Images in different ways to find more information there. In my opinion, it always makes sense to provide additional context. “
Use alt text to provide context
John Mueller basically encourages SEOs and publishers to use words that give context to images in web pages, so that when someone with a screen reader sees the image, it becomes clearer how the image fits into the context of the page content .
So if you’re in doubt about what to put in an image’s alt text, it’s a good idea to think about how to describe the image for people with visual impairments, and then use that description in the alt text.
Citation
SEO for alt text
Watch at the 46:49 minute mark:
