Text scaling

(In development)

Ensure that text in an app can scale to larger sizes. Users specify their preferred font size in the system settings. Text in your app should use the chosen font size.

Impact

Around 35% of all users has adjusted their font size. Around 25% prefers a larger font size.

If text does not scale, people with a visual impairment might not be able to read the text in your app.

Text may not be truncated, meaning that all elements in your app should support multiple lines of text.

Solutions

Elements

Testing

Automated testing

This issue can be detected automatically with the Abra Test Engine.

Manual testing

From the system settings, choose a font size of at least 200%. Or if the app has a font size setting, you can also set it in the app.

  1. Check if text scales to at least 200% or the expected dynamic scaling of the platform.
  2. Check if text is not truncated.

Passes if 1 and 2 are true.

Exceptions

Apps work differently than websites. The Web Content Accessibility Guidelines (WCAG) cannot be applied to apps 1:1.

iOS uses dynamic scaling where large fonts are scaled less in comparison with small fonts. For example, at 350%, headings only scale 190% but body text scales 350%. As a result, almost all text has the same size.

Relevant sources

Always check the official guidelines.