How to write alternative text
Find out more about what alternative text is and how you should write it when adding images to your webpages or digital documents.
What is alt text?
Alternative text, or alt text, is a short description of an image that is read aloud by screen readers and displayed if an image cannot be loaded.
Alt text helps people who are blind or have low vision understand the content of a web page and is an important part of creating accessible websites.
Writing alt text
When writing alt text, ask yourself what information would someone miss if they could not see this image. Focus on the image's purpose rather than describing every visual detail.
Example
- Good: "Students studying together in the university library."
- Less effective: "Three students sitting around a table with books and laptops."
Tips for writing alt text
- Keep it brief and relevant.
- Describe the information or message the image conveys.
- Write in natural language.
- Do not start with phrases such as "Image of" or "Picture of", because screen readers already identify images.Decorative images
Images containing text
You should always avoid using images containing text, especially if the text is not already within the surrounding content. If important information appears in an image, make sure it is included in the alt text or elsewhere on the page.
Example
Image text: "Open Day – 12 October"
Alt text: "University Open Day on 12 October."
Charts and diagrams
Use brief alt text to identify the chart or diagram, then provide the detailed information in the surrounding content.
Example
"Bar chart showing growth in student applications between 2020 and 2025."