How Much Does Alt Text Help SEO?

Whether you’re new to SEO or have spent the last few years trying to optimise your website, you might be unclear on what the purpose of alt text is and if it’s really needed. Writing effective alt text for images can take time and you might be wondering if it actually helps with SEO.  So, is alt text necessary for SEO purposes?

Put simply, yes alt text is a ranking factor for Google image search. This means well-written alt text can help your image, and therefore web page, rank higher in the image search results. It can also have a small impact on your general search rankings, so it’s best to invest some time into learning about and implementing alt text. 

Read on for all the information you need to know, including why alt text is important and our top tips on writing effective alt text to boost your image rankings. 

Does Google Care About Alt Text?

Yes, alt text plays a vital role in getting your images recognised by Google Image Search. Within Google Search Documentation, there is a section on Google Image SEO Best Practices which states:

“The most important attribute when it comes to providing more metadata for an image is the alt text (text that describes an image), which also improves accessibility for people who can’t see images on web pages, including users who use screen readers or have low-bandwidth connections.”

This makes it clear that Google values alt text more than other factors, such as filenames, titles and captions, when it comes to understanding images and ranking them in image search results. However, it’s important to note that Google also uses computer vision algorithms and the contents of the page to understand the subject matter of images. 

So, Is Alt Text a Ranking Factor?

Yes, alt text is an image search ranking factor. According to Google’s John Mueller in a Reddit discussion, human-generated alt text is still a crucial component for images despite an improvement in advanced machine learning models. 

Adding alt text to images allows you to provide the search engine with some much-needed context. Although computer vision might be able to identify what the picture is of, it will not be able to pick up on important contextual clues that link the image to your blog post or landing page. Your alt text might include location information, a product name or a target keyword. For example, if you sell used cars and have a picture of your dealership on your website, your alt text might look something like this: 

“A RAC-approved used car dealership in Sheffield offering a range of competitively priced cars, including Ford, Peugeot and Renault”.

Is Alt Text Important for Organic Search Rankings?

Alt text is clearly an important factor for image search rankings, but what about general organic search? For this, Google treats alt text like any other text on the page. So, although alt text will contribute to your organic search rankings, its impact is limited.

Why Add Alt Text to Images?

Alt text helps Google understand what’s included in an image and helps crawlers index and rank an image properly in image search. To learn more about how Google sees your website, read our blog ‘What Does Google See When It Crawls Your Site?’. 

However, alt text is not just for crawlers, it’s also important for humans and web accessibility. 

Alt Text Provides Context for Humans

One of the primary reasons for adding alt text to images has nothing to do with search engines. Alt text can help users with low vision, visual impairments and different learning abilities to understand images through screen readers, even if they cannot see them. This ensures all users have the same access to content regardless of ability. 

The Web Content Accessibility Guidelines include a wide range of information about making websites more accessible, including guidance on alt text, and is an internationally accepted standard for online compliance.

Additionally, some countries have made alt text a legal requirement to improve accessibility:

• In the United States of America, alt text is required by law under the Americans with Disabilities Act (ADA). This applies to state and local governments and businesses open to the public.
• The European Accessibility Act (EAA) 2025 will require that all images on websites, social media, and email newsletters have descriptive alt text. This is due to come into force on June 28, 2025.

Alt Text Provides Context for Image Search

From an SEO perspective, alt text is important because it can help search engines better understand your images and rank them higher in relevant image search results. 

How to Write Effective Alt Text (with examples)

Google Image SEO Best Practices provides some useful guidance on writing alt text:

“When writing alt text, focus on creating useful, information-rich content that uses keywords appropriately and is in context of the content of the page. Avoid filling alt attributes with keywords (also known as keyword stuffing) as it results in a negative user experience and may cause your site to be seen as spam.

Avoid filling alt attributes with keywords (also known as keyword stuffing) as it results in a negative user experience and may cause your site to be seen as spam.”

So, it’s clear that alt text should contain helpful and descriptive information, with appropriate and relevant keywords. Ideally, alt text should allow you to envision an image and also provide important contextual information that will help your image rank in image search results. 

Look at these examples for this image:

• Bad – “A pyramid” or “A busy street”. These are neither specific nor accurate enough.
• Bad – “Book Louvre museum tour. Louvre museum tour guides. Buy Louvre tickets” These keywords don’t actually describe the image and this is an example of keyword stuffing.
• Okay – “People walking past a famous landmark”. This is accurate, but more information could be provided.
• Better – “People walking past the Louvre Pyramid in Paris”. This gives more information, but it might still be hard for users to picture what the Louvre Pyramid looks like unless they have previous knowledge.
• Best – “People walking past the famous Louvre Pyramid. This iconic glass and metal structure is the entrance to the Louvre Museum in Paris”. This provides enough information to allow users to visualise the image and gives contextual information about what it is in the image and where it is located.

Here are some more examples of bad vs good alt text provided by Google:

Our Top Tips for Writing Effective Alt Text

Although writing alt text is relatively straightforward, writing effective alt text is not quite as simple. Follow our 6 simple tips to write alt text that’s useful for both search engines and humans. 

1. Be Specific

Alt text should allow users to clearly picture the image, even if they are unable to see it. 

2. Use Relevant Keywords

You can use keywords in your alt text, provided they’re relevant to the image and they’re integrated naturally into the sentence. 

3. Avoid Keyword Stuffing

Although using relevant keywords can boost your image’s rankings, you should never ‘keyword stuff’. For example, “cars for sale, used cars for sale, cheap used cars, used car dealership” would not be an effective alt text for a picture of a used car dealership. 

4. Know When Alt Text Isn’t Required

If an image is purely decorative, you can supply an empty alt text (ALT = “”) to mark it as decorative. This is when an image is purely for design purposes and adds no relevant value to the page. 

5. Avoid Redundant Phrases

There is no need to include “picture of” or “image of” at the beginning of your alt text, as this is already assumed. However, if the picture is a screenshot, graph or chart you can specify this within the alt text. 

6. Follow W3C Web Accessibility Initiative guidelines.

For complex images with lots of information, like maps, charts or graphs, it’s best to follow W3C Web Accessibility Initiative guidelines.

Get Help With Your Alt Text From Wildcat Digital 

If you’re struggling with alt text, meta descriptions, title tags or any other element of technical SEO, the team at Wildcat Digital are here to help. Our technical experts are well-versed in all SEO best practices to help improve your website’s rankings and ultimately increase traffic and conversions.

Contact us today for a free initial consultation to find out how we can help your business punch above its weight online.

Alt Text FAQs

What is Alt Text?

Alt text (alternative text) is a type of meta data that describes the appearance, function or importance of an image on a web page. To learn more about different types of metadata, check out our blog, ‘What is Metadata in Laymen’s Terms?’.

How Do I Know if an Image Has Alt Text?

It’s simple to see if an image has alt text by inspecting the HTML code. Right-click on the image and choose “inspect” to open up Chrome DevTool. You can then look, or search, for the img alt.

What Does Alt Text Look Like?

The <img> tag has two required attributes: 

• src which specifies the path to the image. 
• alt which specifies an alternate text for the image.

Here’s an example of what this looks like in HTML:

<img src=”laptopworking.jpg” alt=”alt=A man writing a blog about digital marketing on a laptop”>

How to Add Alt Text to Images

The good news is that you don’t need to be a developer to add alt text to images as many content management systems will easily allow you to add alt text when uploading content.

Who Is Alt Text For?

Alt text is descriptive text designed to help with accessibility. Users with visual impairments or low vision use screen readers to understand internet content, including images. Alt text is read aloud by screen readers to help these users better understand web pages. It is also displayed if an image fails to load and is an important ranking factor for Google image search. 

Can Alt Text Have Spaces?

Yes, alt text can have spaces and should be written like a normal sentence.

Can Alt Text Have Special Characters?

It’s generally recommended to avoid special characters in alt text. 

Can Alt Text Be Too Long?

Google has no official guidelines on how long alt text should be and there is no character or word limit. 

However, it’s best to use common sense when writing alt text. Your alt text should be long enough to be descriptive with any relevant information a user or search engine might need to understand the image, without being unnecessarily wrong. Remember that screen readers will read out your alt text to visually impaired users. Typically one or two sentences should be enough.