Accessibility Tips: Dos and Don’ts for Alternative Text

Alternative text, also known as alt text, describes the content and purpose of an image, chart, or table for people who have visual impairments or use screen reading technologies. 
 
All images, charts, and tables require some form of alt text. The alt text should provide the information a person needs to know about the image, chart, or table to make it relevant to the content. Complex visual components, like tables, charts, and infographics, may need a more detailed description than an image. 

Experience the Benefits of Helpful Alt Text

Review the following simulation video to experience the benefits of well-written alt text.

Best Practices for Writing Alt Text

Dos

• DO describe the relevant content and purpose of the image. There is no need to describe every visual detail.
• DO keep alt text short. Between 1-2 sentences should effectively communicate the image’s message and purpose. Some screen readers cut off alt text at 125 characters. 
• DO use proper punctuation. Without proper punctuation, screen readers cannot speak the alt text in the natural manner the author intended. Remember to always end the alt text with a period. 
• DO avoid using text in images. Screen readers cannot access the text written inside images. If text within an image is unavoidable, the text should be written word-for-word in the alt text or, even better, somewhere else in the document’s text content.
  • Text in images also introduces another category of accessibility concerns: color. Low color contrast, for example, can be a problem for all users, regardless of vision. For more about color, review our previous article on Microsoft Office Accessibility Tips.
• DO stay consistent with language. If your content is written in Spanish, your alt text should also be written in Spanish. If you translate that document into English, your alt text must also be translated into English.

Don’ts

• DON’T describe every detail of the image. Typically, only graphs, charts, and tables should have alt text longer than 1-2 sentences. 
• DON’T start the alt text with “Image of” or “Picture of”. Screen-reading technology makes this a redundancy.
  • DO start with the image type for specific formats like logos, illustrations, paintings, cartoons, maps, etc.
• DON’T repeat information in alt text that is already in the text content of the document, webpage, or image caption.
• DON’T rely on AI-generated alt text. AI-generated text is unable to consider the context or purpose of your document as a whole. If you choose to use AI-generated alt text, always review the content before sharing or publishing.
• DON’T forget to mark an image as “decorative” if it does not provide additional needed context or information. Decorative images are skipped by screen readers.
  • Oftentimes, empty alt text does not automatically mark an image as decorative. Empty alt text often results in the screen reader just reading the file name of the image.

How to Add Alt Text in Microsoft Office

In all Microsoft Office applications, you can access the Microsoft Accessibility Checker through the Review tab, typically located to the left of the View tab. This includes Word, PowerPoint, Excel, and OneNote. The appearance of the button for the Accessibility Checker is different in desktop and web views.

After running the Accessibility Checker, any issues like missing alt text or table headers will be identified and available for you to fix in the Accessibility sidebar on the right side of your screen.

Upcoming Workshops

Accessibility Tips: Microsoft Office

Tuesday, February 24, 2026 (2 – 3 p.m.)

Resources

• Accessibility Resources 
• Microsoft Office Accessibility Tips 
• MyCourses Digital Content Accessibility Requirements