what is Alt Text and how to use Alt Text

Alt text (alternative text), also known as "alt attributes", “alt descriptions,” and colloquially but technically incorrectly as "alt tags,” are used within an HTML code to describe the appearance and function of an image on a page.


The best format for alt text is sufficiently descriptive, but doesn't contain any spammy attempts at keyword stuffing. If you can close your eyes, have someone read the alt text to you, and imagine a reasonably accurate version of the image, you're on the right track.

Why is alt text important?

1. Accessibility

Alt text is a tenet of accessible web design. Its original (and still primary) purpose is to describe images to visitors who are unable to see them. This includes screen readers and browsers that block images, but it also includes users who are sight-impaired or otherwise unable to visually identify an image. Including alt text with your images ensures all users, regardless of visual ability, can appreciate the content on your site.

2. Image SEO

Using alt text on your images can make for a better user experience, but it may also help earn you both explicit and implicit SEO benefits. Along with implementing image title and file naming best practices, including alt text may also contribute to image SEO.

While search engine image recognition technology has vastly improved over the years, search crawlers still can't "see" the images on a website page like we can, so it's not wise to leave the interpretation solely in their hands. If they don't understand, or get it wrong, it's possible you could either rank for unintended keywords or miss out on ranking altogether.

How do I write good alt text?

1. Describe the image as specifically as possible. Alt text is, first and foremost, designed to provide text explanations of images for users who are unable to see them. if an image truly doesn't convey any meaning/value and is just there for design purposes, it should live within the CSS, not HTML.
2. Keep it (relatively) short. The most popular screen readers cut off alt text at around 125 characters, so it's advisable to keep it to that character count or less.
3. Use your keywords Alt text provides you another opportunity to include your target keyword on a page, and thus another opportunity to signal to search engines that your page is highly relevant to a particular search query. While your first priority should be describing and providing context to the image, if it makes sense to do so, include your keyword in the alt text of at least one image on the page.
4. Avoid keyword stuffing. Google won't dock you points for poorly written alt text, but you'll be in trouble if you use your alt text as an opportunity to stuff as many relevant keywords as you can think of into it. Focus on writing descriptive alt text that provides context to the image and if possible, includes your target keyword, and leave it at that.
5. Don't use images as text. This is less of an alt text-specific best practice and more of a general SEO-friendly web development tenet. Because search engines can't read text within your images, you should avoid using images in place of words. If you must do so, explain what your photo says within your alt text.
6. Don't include "image of," "picture of," etc. in your alt text. It's already assumed your alt text is referring to an image, so there's no need to specify it.
7. Don’t forget longdesc="". Explore using the longdesc="" tag for more complex images that require a longer description.
8. Don’t neglect form buttons. If a form on your website uses an image as it’s “submit” button, give it an alt attribute. Image buttons should have an alt attribute that describes the function of the button like, "search", "apply now", “sign up,” etc