There’s a lot you can do to improve SEO on your site, but one of the simplest is optimizing the alt-text. It’s not a major factor in your ranking, but every little adjustment counts and when it is this simple, how can you possibly refuse?

    Today we outline the ten things you need to know about alt-text, SEO, and how to make your images work for you on Google, Bing, Yahoo, and beyond.

    What is alt-text?

    Let’s start with a confession. Alt-text is not alt-text. Alt-text is actually a contraction, a shorter version of ‘alternative text’ – and that provide a clue as to what alt-text actually is. Alt-text is a part of the code related to an image, and it serves as an alternative to the image if the image itself is unavailable. It looks something like this:

    <img src-“8-things-you-need-to-know-about-alt-text.png” alt-“8 Things You Need to Know About Alt-Text Header”>

    Why is it important?

    There are two groups of people that find alt-text really useful.

    The first are those with accessibility issues. For example, people with difficulties reading webpages because of problems with their vision often use screen reading software to ‘speak’ the webpage to them. When this software encounters an image that, obviously, cannot be ‘spoken’, the software instead reads the alt-text out loud.

    The second group of people that find alt-text useful are not people. They are robots. Specifically, they are the robot crawlers and bots that search engines send across the web to discover your site. The alt-text helps the bots to understand more about the context of the image and the text on the page, and will usually aid in ranking the image in specific image search engines, too. As a result, alt-text is an on-site SEO factor.

    What must be included in the alt-text?

    In simple terms, the alt-text should be a plain English description of the image. The more detailed the alt-text, the better off you will be.

    Imagine you are in the business of selling electronics and you include an image of a portable computer on your site. Which of the following is the best example of alt-text for an image on your site:

    • computer;
    • laptop computer;
    • apple laptop computer;
    • apple macbook air laptop computer; or
    • apple macbook air 13 inch laptop computer

    Yes, the last one is the best. If your electronics store is selling different types of laptop computers you’ll want the image you use to include the alt-text that explains the brand, the size, and the model. Remember, one of the groups that relies on alt-text are those who cannot tell that your picture of a ‘laptop computer’ is from Appel and not Lenovo simply by looking.

    Does this mean I should use keywords?

    Yes. Using keywords in the alt-text is smart and provides additional ranking help for your page (hopefully you’ve optimized the image and the page to the same keyword).

    Note, though, that search engines do not reward keyword ‘stuffing’. Hence, you don’t want to label that image of the laptop with the alt-text:

    apple laptop macbook laptop aid laptop 13 laptop inch laptop computer

    Not only will you feel kinda silly typing that out, but you’ll cop a SEO penalty for doing it.

    Instead, keep it natural, keep it specific, keep the keywords, but don’t ‘stuff the alt-text with keywords hoping for a reward.

    What about formatting?

    Remember that example tag from earlier in the post?

    <img src-“8-things-you-need-to-know-about-alt-text.png” alt-“8 Things You Need to Know About Alt-Text Header”>

    The part of the tag that comes first (8-things-you-need-to-know-about-alt-text.png) is the title of the file. If you downloaded that file then that would be the name of the film, hyphens included.

    But note that the alt-text (8 Things You Need to Know About Alt-Text Header) doesn’t include the hyphens? That’s because, as mentioned earlier, the alt-text needs to be natural text. Imagine the screen reading software going over your text and match your alt-text to what you’d like someone to read aloud to another – easy, right?

    How long should my alt-text be?

    OK. So you understand that the alt-text is a natural, English language description of the image, but how long should that description be?

    Testing in 2014 and 2015 suggests that 16 words is the maximum number of words that a Googlebot will crawl in the alt-text of an image. In reality, 16 words is more than enough for most images. As demonstrated in our apple laptop example above, at seven words we have explained the make, model, size, and type of product. A couple more words might tell us the speed and memory of the product, but it would be a stretch to get out to 16 words.

    Note that you can include more than 16 words, but the evidence suggests that the Googlebot just ignores these.

    As long as you keep your alt-text to 16 words or less, fit in the keywords you are optimizing for, and match those keywords to the keywords on the page, you should be fine for length.

    Should I use alt-text for every image on my site?

    No, there are some exceptions. Let me explain.

    You should use alt-text on the feature images on your blog, the images you use on your website, your headers, in your sidebars, in posts and on pages, and throughout any visual content that you produce and publish online that Google or other search engines will crawl.

    So what do you avoid? In other words, what is left?

    Things that don’t serve a purpose as images are things to avoid adding alt-text to. Things like bullets used to make a list, or horizontal spacers or bars that serve to break up a webpage. A background element that is an image instead of part of the style sheet may not benefit from alt-text, and anything that doesn’t add to the information or value of the page need not have alt-text.

    Should I include information about the size of the image in the alt-text?

    No. Keep you text to useful information that could serve as an alternative to the image in case it could not be rendered. While the alt-text ‘8 Things You Need to Know About Alt-Text Header’ is useful, the alt-text ‘8 Things You Need to Know About Alt-Text Header 1024px512px’ is not.

    Leave the size of the images for the back end, and keep the alt-text for the keywords and descriptions that will help in your SEO efforts.


    Getting your alt-text right is a small part of your on-site SEO effort, but it is an important part. If your images are optimized for search and if you make your site more accessible for those who have issues reading a site normally, you’ll see a pay off in terms of rankings and in terms of traffic, too.

    Do you have any other alt-text tips? Let us know on Twitter!



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    3. Hello there,

      Great article. If I have an ecommerce store that sells beads and I need to write the alt tags for 5 photos of the same items (5 angles), what is your suggestion. The reason I’m asking this is do I have to include alt tags for all 5 images or do I have to write an alt tag for just the first photo?

      Example: Citrine Beads
      My Primary, Secondary, Tertiary keywords might be Citrine Beads, Citrine Stone, Citrine Gemstone.

      If I need to write 5 alt tags for all of the pictures because they are at different angles, would you recommend using any of the keywords since it describes the item? And if so, how do i write it for the different angles. I would love your advice on this.

      Would this be correct for my 5 alt tags
      Citrine Beads Faceted Round
      Citrine Stone Faceted Round
      Citrine Beads Faceted Round Side
      Citrine Stone Faceted Round Top
      Citrine Beads Back

      Many thanks in advance.

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