Alt Text Tag Guide: What Is It, How to Use It?

Jul 02 2024 by Oskay Günaçar

What Is Alt Text Tag?

An alt text tag, also known simply as "alt text," is a description added to the HTML code of an image using the alt attribute. It helps screen readers interpret the image content for visually impaired users and aids in image indexing for search engines, enhancing SEO and providing a textual substitute when the image fails to load.

Syntax of Alt Text Tag

An Alt tag is embedded within the HTML code of a webpage. It's typically found within the <img> tag, an HTML element used to embed images. The Alt attribute is added to this tag, and the value assigned to it is the descriptive text.

For instance:

<img src="" alt="A descriptive text of the image">.

This structure ensures that if the image fails to load, or if a user can't visually perceive the image, the descriptive text is displayed or read out loud by screen reading software.

Here's a breakdown of the syntax:

  1. Basic Structure: The basic structure of an Alt tag within an image tag looks like this:

    <img src="" alt="Descriptive text of the image">

    In this structure:

    • <img> is the tag used to insert an image.
    • src (source) attribute specifies the path or URL to the image file.
    • alt is the attribute used for the alternative text.
  2. Alt Attribute: The alt attribute is where the alternative text is placed. This text should be a concise and accurate description of the image.

    For example:

    <img src="" alt="A brown dog playing fetch in a park">
  3. Handling Decorative Images: If an image is purely decorative and adds no informational content to the site, you can use an empty alt attribute. This is done by still including the alt attribute but without any text, like so:

    <img src="" alt="">

    This approach is used to tell assistive technologies like screen readers to ignore the image.

Alt Text Tag Usage Example

A silver laptop open on a wooden desk with a cup of coffee beside it.

 For example, when you use an image like the one above on your web page, you can edit the alt tag text of this image as follows;

<img src="" alt="A silver laptop open on a wooden desk with a cup of coffee beside it.">

 The image whose alt text tag you edited will be displayed in the source code like the example below;

Why Is the ALT Attribute Needed For?

The Alt Text Tag is crucial for enhancing web accessibility for visually impaired users, improving SEO by aiding image indexing, and providing textual backup when images cannot be displayed and ensuring all users understand the content.

Understanding the ALT Attribute

The ALT attribute, commonly referred to as "alt text," is an essential component in web development used within the <img> tag in HTML. It serves several critical functions that enhance user experience and website performance.

Enhancing Web Accessibility

Alt text is primarily used to improve accessibility for visually impaired users who rely on screen readers. These devices read aloud the text associated with images, allowing users to understand the content that they cannot see. Without alt text, those users might miss out on important visual information.

Boosting SEO Performance

Search engines index images using alt text, which provides context about the image's content. Well-crafted alt text can improve a website's SEO by helping it rank in image search results and enhancing the overall relevance of the page to search queries.

Providing a Textual Backup

The alt attribute serves as a fallback solution when an image file cannot be displayed due to loading errors or if images are turned off in a user's browser settings. In these scenarios, the browser displays the alt text instead of the image, ensuring that the message or function of the image is not lost.

Supporting User Experience in Slow Networks

In environments with slow network conditions, images might take longer to load or not display properly. Alt text can provide immediate context about the missing images, which can be crucial for understanding the webpage content without waiting for all media to load.

Facilitating Better Content Management

In content management systems, alt text can help content creators understand and manage media files more effectively. It can act as a descriptive label, making it easier to search for and organize media in large databases.

Benefits of Using Alt Text For SEO

Improved Image Indexing

Alt text provides search engines with clear descriptions of what images depict, allowing them to index images accurately. This detailed indexing helps images appear in search results when users query related terms, thereby driving traffic to your website.

Enhanced Keyword Optimization

Including relevant keywords in alt text can boost your website's SEO by aligning it more closely with search queries. This practice should be done judiciously to avoid keyword stuffing, ensuring the text remains descriptive and relevant to the image content.

Increased Accessibility and User Engagement

Websites that are accessible to all users, including those with visual impairments, tend to rank better in search results. Alt text makes images accessible to screen readers, contributing to a better overall user experience, which is a factor in SEO rankings.

Supports Context and Relevance

Alt text helps provide context to the images, which enhances the overall relevance of the webpage to specific search queries. This relevance can increase the page's authority and its ranking in search results.

Boosts Performance in Image Search

With well-optimized alt text, images are more likely to appear in targeted image searches, leading to increased visibility and traffic. This is particularly beneficial for websites relying heavily on visual content, such as e-commerce sites where images directly influence buying decisions.

Fallback for Missing Images

If an image fails to load due to a slow connection or an error, the alt text will be displayed in its place. This ensures that the intended information is not lost, providing continuity and a seamless user experience, which are positive signals to search engines about the quality of the website.

Importance of Alt Text Tags For Web Accessibility

The importance of Alt tags for web accessibility cannot be overstated. These tags play a crucial role in ensuring that digital content is inclusive and accessible to all users, particularly those with visual impairments. Below are the key reasons why Alt tags are vital for web accessibility:

  1. Enabling Screen Reader Accessibility: Alt tags provide descriptions of images for users who rely on screen readers. These assistive technologies read out loud the contents of a webpage, including the Alt text associated with images. Without Alt tags, visually impaired users may miss critical information conveyed through images, leading to an incomplete understanding of the webpage content.

  2. Fulfilling Legal and Ethical Standards: Many countries have laws and regulations, such as the Americans with Disabilities Act (ADA) in the United States, that require digital content to be accessible to people with disabilities. Alt tags are part of these requirements. By including Alt tags, website owners not only comply with these legal standards but also uphold ethical standards of inclusivity and equal access.

  3. Facilitating Better User Experience in Varied Situations: Besides benefiting users with visual impairments, Alt tags also enhance the user experience in situations where images fail to load due to slow internet connections or technical glitches. Instead of seeing a blank space or a broken image icon, users see a descriptive text, which keeps the flow of information uninterrupted.

  4. Providing Contextual Information: In some cases, images may contain critical information or contribute significantly to the content's context. Alt tags ensure that this information is not lost to users who cannot see the images, thereby maintaining the content's integrity and intended message.

  5. Supporting Diverse User Needs: Beyond those with visual impairments, Alt tags assist users with cognitive disabilities who may use text-to-speech software, users in noisy environments where images might not be easily viewed, and those who prefer textual over visual information for various reasons.

  6. Enhancing Navigation: For users navigating a website with a keyboard or through voice commands, Alt tags can provide necessary cues about where the links within the images will lead, improving the overall navigability of the website.

In conclusion, Alt tags are a fundamental element in making web content accessible to a diverse range of users. They ensure that the web remains an inclusive space, where information is available to everyone, regardless of their physical abilities or the limitations of their environment. By implementing Alt tags effectively, web developers and content creators can significantly enhance the accessibility and usability of their websites.

What Content Should the ALT Tags Have?

Crafting effective ALT text involves several key considerations to ensure it is both informative and functional.

Descriptive and Contextual Relevance

The ALT text should accurately describe what is shown in the image. This description should be concise yet detailed enough to convey the image's content and purpose within the context of the surrounding text. For instance, if the image is a chart illustrating sales trends, the ALT text should describe the type of chart and the trend it shows, such as "Bar chart showing an increase in sales for the first quarter."

Incorporate Keywords Strategically

Including relevant keywords in the ALT text can aid in SEO, as it helps search engines understand the image. However, the primary purpose of ALT text is to describe the image, so keyword inclusion should feel natural and relevant to the image's content. Avoid keyword stuffing, as this can negatively impact SEO and user experience.

Handling Decorative Images

For images that are purely decorative and do not add informational content to the page, such as borders or stylistic elements, the ALT text can be left empty. This approach tells screen readers to skip these images, preventing unnecessary clutter in the auditory experience of visually impaired users.

Length of ALT Text

The ALT text should be brief and to the point. A general guideline is to keep it under 125 characters. This length is sufficient to convey necessary information without being overly verbose, making it more usable for screen reader users and search engines.

Avoid Redundant Phrases

Phrases like "image of" or "graphic of" in the ALT text are generally unnecessary, as screen readers already announce the presence of an image. Directly starting with the description is more efficient and user-friendly.

Describe Functional Images Appropriately

If an image is used as a button or link, the ALT text should describe the function, not just the appearance. For example, for an image used as a search button, ALT text like "Search" is more appropriate than "Magnifying glass."

In summary, the ALT tag content should provide an accurate, concise description of the image, contextualized within the webpage content. It should be thoughtfully crafted to enhance user experience for those using screen readers, while also being mindful of SEO best practices. Effective ALT text contributes significantly to making web content accessible, inclusive, and optimized for search engine rankings.

How to Add Alt Text Tags to Images

Adding alt text to images is a simple yet crucial step in web development, ensuring accessibility and improving SEO. Here’s how you can add alt text to images in various common contexts:


For a website, you directly include the alt text in the <img> tag in your HTML code:

<img src="" alt="A concise description of the image">


If you're using WordPress:

  1. Go to your page or post editor where you want to insert an image.
  2. Click on “Add Media” to upload or select an image.
  3. Once the image is selected, fill in the “Alternative Text” field with a description of the image.
  4. Insert the image into your page or post.


For Shopify stores:

  1. Navigate to the section where you manage products, collections, or blog posts.
  2. Click to edit a product or post.
  3. In the image settings (after clicking on an image), there will be an “ALT” field.
  4. Enter your alt text in this field and save your changes.


In Squarespace:

  1. Click on the image you want to edit.
  2. Choose “Edit” or click the pencil icon.
  3. In the image settings, find the “Alt Text” field.
  4. Provide your description and apply the changes.

Social Media Platforms

Many social media platforms like Facebook, Instagram, and Twitter now allow you to add alt text to images:

  • Facebook: When uploading an image, click on “Edit” and fill in the “Alternative Text” field.
  • Instagram: Before posting an image, go to “Advanced Settings” and then “Write Alt Text.”
  • Twitter: After uploading an image, use the “Add description” button to provide alt text.

Email Marketing Platforms

For platforms like Mailchimp:

  1. When creating an email, click on an image block to add or edit an image.
  2. After uploading/selecting an image, look for the “ALT” text option in the image settings.
  3. Enter your description and save your changes.

Adding alt text is a straightforward process, but it's vital to ensure that the descriptions are accurate and helpful for those using screen readers. This practice not only supports accessibility but also enhances the image's visibility to search engine crawlers, contributing to better SEO outcomes.

Tips and Best Practices for Writing Image Alt Text Tags

Writing effective alt text tags is crucial for both accessibility and SEO. Here are some tips and best practices to help you craft useful and SEO-friendly alt text:

1. Be Descriptive and Specific

Focus on describing the image accurately. Use specific details that are relevant and give context. For instance, instead of "dog," say "a golden retriever puppy sleeping on a blue blanket."

2. Keep It Concise

Although detailed, try to keep your alt text concise—usually under 125 characters. This length is enough to describe the image meaningfully without being overly verbose, as some screen readers cut off alt text at around this length.

3. Avoid Keyword Stuffing

Incorporate relevant keywords naturally when they are appropriate but avoid stuffing your alt text with keywords, as this can negatively impact your SEO and degrade the user experience.

4. Skip “Image of…” or “Picture of…”

Screen readers typically announce an image as an image, so starting your alt text with phrases like "image of" or "picture of" can be redundant. Directly describe what the image is about.

5. Use Functional Descriptions for Actionable Images

If the image serves a function (like a button), describe the function, not just the appearance. For example, use "Search button" instead of just describing the icon used.

6. Include Text Present in the Image

If your image includes text that’s key to understanding the content, make sure to reproduce this text in the alt attribute. This ensures that all users, regardless of visual capability, receive the full content of the image.

7. Consider Cultural Relevance

Be mindful of cultural significance and nuances that might affect how an image is perceived. Descriptions should be culturally appropriate and sensitive.

8. Test with Screen Readers

To ensure your alt text serves its purpose, test it with screen readers to see how it would be interpreted by visually impaired users. Adjust based on the feedback or any awkward pronunciations or contexts.

9. Update Alt Text as Needed

If the context or function of an image changes on your site, remember to update the alt text accordingly. Alt text should always reflect the current role and content of the image.

10. Use Empty Alt Attribute for Decorative Images

If an image is purely decorative and adds no informational content, it’s often best to use an empty alt attribute (alt=""). This tells screen readers to skip over the image, simplifying navigation for visually impaired users.

What Does Good Alt Tag Text Look Like

Good alt tag text, or alt text, effectively describes the content and purpose of an image in a concise, clear manner. Here’s what good alt text generally looks like:

Descriptive and Informative

Alt text should accurately describe what is happening in the image and include context that is relevant to the content of the page. For example, if there’s an image of a person giving a presentation at a conference, the alt text could be "John Doe presenting on market trends at the 2024 Digital Marketing Conference."


While being descriptive, alt text should also be concise—typically no more than 125 characters. This balance ensures it is long enough to be descriptive, yet short enough to avoid overwhelming the user or being cut off by screen readers.


The description should be objective and not include subjective or promotional language unless it directly relates to the image's content. Avoid interpretative language unless it's a critical part of the image's meaning.

Functionality Described

If the image has a specific function (like a button or link), the alt text should describe the function, not just the appearance. For instance, an image used as a search button should have alt text like "search button" or "submit search."

Inclusion of Text in Images

If the image includes text that’s crucial to understanding the content, the alt text should also include that text. For example, if an image is a graph with key data, include the main data points and what the graph represents.

Absence of Redundant Phrases

Avoid phrases like "image of" or "photo of" since screen readers often provide that context automatically. Jump straight into describing the image itself.

Consider Context

Alt text should be tailored to the function of the image within the specific context of the page. An image may need different alt text depending on how it is used in different parts of the website.

Example of Good Alt Text:

  • Poor Alt Text: "Logo"

  • Better Alt Text: "Storyly company logo"

  • Poor Alt Text: "Dog"

  • Better Alt Text: "Labrador retriever catching a frisbee in a park"

  • Poor Alt Text: "Graph"

  • Better Alt Text: "Bar graph showing a 30% increase in traffic from January to February 2024"

These examples reflect the principles of good alt text by being clear, concise, and relevant to the context, thereby improving both accessibility and SEO.

How Long Can Alt Text Tag Be?

The length of alt text can technically be as long as needed, but for practical and usability reasons, it can typically be up to 125 characters long, though some recommend a maximum of 150 characters to ensure accessibility and effectiveness.

Here are some key considerations for determining the optimal length:

Recommended Length

Most guidelines suggest keeping alt text to about 125 characters or fewer. This length is enough to provide a meaningful description without being overly verbose. Screen readers may handle longer alt text differently, but shorter alt text ensures a smoother user experience.

Screen Reader Considerations

Different screen readers have different behaviors when handling long alt text. Some may cut off the text after a certain number of characters (often around 125 to 150 characters). Keeping the alt text within this limit ensures that the entire description is heard.

SEO Implications

While search engines can process longer alt text, concise descriptions are typically more effective. Conciseness ensures that the alt text remains focused on the most relevant keywords and the primary function or content of the image.

Context and Content

In some cases, more detailed descriptions may be necessary, especially if the image contains complex information like graphs, charts, or infographics. In these situations, ensure that the alt text conveys the essential information, even if it slightly exceeds the typical length.

Practical Example:

Instead of "A small dog with a fluffy brown coat and a red collar playing fetch with a bright green tennis ball in a sunny park with lots of trees and children playing in the background," simplify it to "Small brown dog playing fetch with a tennis ball in a sunny park."

Is Alt Text Tag a Ranking Factor?

Yes, alt text is considered a ranking factor in search engine optimization (SEO). Here’s how it contributes to your website’s search engine performance:

1. Improves Image Search Rankings

Alt text provides search engines with a textual description of an image. Well-crafted alt text can help your images rank higher in image search results, as it allows search engines to understand the content and context of the image, making it more likely to appear in relevant searches.

2. Enhances Overall SEO

By providing context about the images, alt text helps search engines understand the overall content and theme of your webpage. This additional context can improve the relevance of your page for specific search queries, potentially boosting your page’s ranking in search results.

3. Increases Accessibility

Search engines favor websites that provide a good user experience, and accessibility is a significant component of that. Alt text makes your website more accessible to individuals with visual impairments by enabling screen readers to describe images. Websites that are accessible are often ranked higher by search engines.

4. Supports Context and Keywords

Incorporating relevant keywords into your alt text can support your SEO strategy by aligning with the textual content of your page and the search terms your target audience might use. This needs to be done naturally and contextually to avoid being penalized for keyword stuffing.

5. Assists in Indexing

For web pages that heavily rely on visual content, alt text can be especially important as it helps search engines index the content properly. Proper indexing is crucial for visibility in search results.


In the digital age, where visuals dominate the web landscape, alt text stands as a crucial but often overlooked component that enhances both accessibility and SEO. By providing a textual description of images, alt text ensures that all users, regardless of their ability to see, can appreciate and understand the content on your website. Moreover, it plays a significant role in boosting your website's visibility in search engines by helping to accurately index and understand the content of images.

As we've seen, implementing effective alt text is not merely a technical requirement—it's a commitment to inclusive and optimized web content. From improving user experience on slow networks to supporting robust content management systems, alt text enriches user interaction and engagement across various platforms. Whether you're managing a personal blog or a large e-commerce site, the thoughtful inclusion of alt text can significantly influence your site's performance and user satisfaction.

By adhering to best practices for writing alt text, you can ensure that your site remains accessible, relevant, and favored by search engines. Remember, every image offers an opportunity to enhance accessibility and optimize your site for better search rankings. Take these opportunities to review and refine the alt text across your website, making your digital space welcoming and accessible to all, while also driving traffic through improved SEO. The power of alt text is profound and leveraging it effectively is an essential stride towards building a more inclusive and visible web presence.

Oskay Günaçar
Oskay Günaçar is a Technical SEO expert and backend developer. His main areas of interest are back-end programming, Python, Django, Go, semantic SEO, technical SEO. With more than 5 years of SEO experience, he has held SEO specialist positions at İkiler, Webtures, Boosmart, and companies, and has been involved in numerous projects as an outsourced expert. Through the TechSEOHub website, he aims to share the expertise and experience he has gained from managing and developing (SEO) processes for many successful and large websites in the industry, and to produce content for easy access to accurate and high-quality information.