Alt text is a short written description added to an image that explains its content or purpose. It helps:

• Screen reader users understand images they cannot see
• Everyone better understand visuals when paired with captions
• Create accessible content for learners and improve how search tools index your files

Since alt text can be read by screen readers, blind and low vision users rely on it to fully understand your content. 

Optional Tools for Writing Alt Text 

AI tools can help generate starting points for alt text, but they always need human editing and review. 

Recommended tool: 

• ASU Image Describer (Free)

Keep in mind: 

• AI cannot determine if an image is decorative
• Always verify accuracy and relevance before use
• Never upload images containing private or student information

Not every image needs the same type of description. Decide whether it should have alt text, a long description, a caption, or be marked as decorative. 

• Instructional images add value to the content and need alt text. These include charts, diagrams, and visuals that explain or reinforce ideas.
• Decorative images are only for visual appeal and can be marked as decorative if removing them would not change the message.
  • Ask yourself, “Could I replace this image with a doodle of a flower without changing meaning?” If yes, it is decorative.
• Long descriptions or captions are used when the image contains too much information for short alt text. If your alt text is longer than 120 characters, switch to a caption or long description that provides additional details. 

When writing alt text, focus on what the reader needs to know. 

Tips for creating clear and useful alt text: 

• Keep it concise (around 120 characters)
• Focus on purpose and context — describe what the image communicates
• Stay objective and describe what you see, not what you assume
• Do not start with “image of” — screen readers already announce image types
• Mention the image type only when it adds context (for example, “bar graph showing enrollment trends”)
• If the image is complex, provide short alt text and include a caption or long description elsewhere in the document 

You can add alt text to pictures, charts, tables, shapes, and SmartArt graphics. There are three ways to do this in Word. 

Option 1: Select and Right-Click 

1. Select the image, shape, or graphic.
2. Right-click the content and choose View Alt Text.
3. Add a brief and clear Description.
4. If the image is decorative, check Mark as decorative x so screen readers skip it. 

Option 2: Use the Accessibility Checker or Accessibility Assistant 

1. Go to the Review tab.
2. Select Check Accessibility or Accessibility Assistant.
3. Follow the prompts to add missing image descriptions directly from the inspection results. 

Option 3: Use the Ribbon 

1. Select the image.
2. On the top ribbon, select Picture Format.
3. Choose Alt Text from the Accessibility group.
4. Enter your description in the panel that appears. 

Tables and charts should always include captions, but not all tables require alt text. 

• Charts always need alt text because they convey data, trends, or relationships that are not visible to screen reader users.
• Tables only need alt text if they are complex, such as when they:
  • Contain merged or blank cells
  • Include multiple data sections or subsections
  • Present a large amount of data that needs context 

You will note this information in the alt text to improve understanding for a screen reader user. 

How to add alt text: 

1. Right-click the table or chart and choose Table Properties or Format Chart Area.
2. Select the Alt Text tab or option.
3. Add a short description explaining what the data or chart represents.
4. Always include a caption above the table or chart that summarizes key takeaways.
   • Example: 
     Table 1. Enrollment numbers by semester 
     Alt text: “Table showing enrollment increases each semester from 2021 through 2025.” 

If your alt text is longer than 120 characters or the image is too complex for a brief description, switch to a caption or long description. 

Use a caption when: 

• The image is too detailed for concise alt text
• You want to summarize the image’s meaning for all readers 

Use the Insert a caption for a picture Microsoft guide to learn how to add a caption to a picture. In the alt-text for that picture, indicate where to find the full description (for example, “Refer to Figure 3 caption below”). 

Use a long description when: 

• The explanation is longer than three or four sentences
• The image contains layered or complex information 

Place long descriptions at the end of the document or on a linked page. In your alt text, indicate where to find the full description (for example, “Refer to [section where long description is located] ). 

1. Go to the Review tab in Word.
2. Select Check Accessibility.
3. Confirm that no images are flagged as missing descriptions.
4. Save your document.
5. When exporting to PDF, use our Saving Word and PowerPoint (PPT) Files to PDF Guide or a more accessible PDF export. 

For more, review these additional resources: 

• Word Accessibility Part 1: Creating Accessible Word Documents (video)
• Word Accessibility Part 2: Fixing Inaccessible Word Documents (video)
• Creating Accessible Word Documents
• Alt Text 101: Basics, Decorative Images, and How AI Can Help (video)

For support, email [email protected].