Alt Text

Alt text refers to a written description of an image on a web page, attached to that image as an HTML element. This HTML element was originally conceived in the early history of the internet, when some browsers were strictly text based. These days however, it’s simply used to help users visualise an image if they can’t see it in detail for any reason, for example if they’re visually impaired.

What Does Alt Mean?

The “alt” in “alt text” is a contraction of “alternative”. Alt text is so labelled because the text is intended to act as an alternative to seeing the image.

Why Does Alt Text Matter?

SEO professionals need to consider how they use alt text for two key reasons.

Firstly, using alt text will improve the user experience and accessibility of a site, and allow site visitors to access all the image content on a page, even if they’re blind or visually impaired. It can also be helpful for web users who have certain learning disabilities or conditions that affect their sensory processing. Alt text can also make a site more accessible in rare cases where a page doesn’t load properly or a site user has opted not to view images.

The second reason to think about alt text in an SEO context is that the descriptions you use in them can provide important semantic cues that search engines use to rank images in search results. The more accurate and helpful your alt text is, the easier it will be for Google to understand and rank your content.

Alt Text Best Practices

With each piece of alt text you write, the most important thing is to keep it succinct and specific.

Some screen reading tools have a character limit for every instance of alt text they read, so make sure that you’re keeping within 125 characters to avoid them stopping short. The vast majority of alt text fields can be filled effectively with just a few words, though complex images (e.g. graphs with detailed legends) could require a more detailed sentence.

Though it’s good practice to keep alt text short, it’s also important to be descriptive and specific about what the image contains. For example, if you were describing an image from a football match, the alt text should name the players in frame and the league or tournament the match is a part of, and not something vague like “footballer kicking ball”.

When writing alt text for images, one of the easiest ways to stay on the right track is to imagine you’re describing the image in front of you over the phone, and trying to give the person you’re speaking to an accurate idea of it in as few words as possible.