Resize text

About

Version:	WCAG 2.0 and up
Number:	1.4.4
Level:	AA
Applicability:	Text
Requirement:	Except for captions and images of text, text can be resized without assistive technology up to 2.0 percent without loss of content or functionality.
Guidance:	Understanding Success Criterion 1.4.4 How to meet Success Criterion 1.4.4
Techniques:	C12: Using percent for font sizes C13: Using named font sizes C14: Using em units for font sizes C28: Specifying the size of text containers using em units G142: Using a technology that has commonly-available user agents that support zoom G146: Using liquid layout G178: Providing controls on the Web page that allow users to incrementally change the size of all text on the page up to 200 percent G179: Ensuring that there is no loss of content or functionality when the text resizes and text containers do not change their width SCR34: Calculating size and position in a way that scales with text size

Purpose

The purpose of this success criterion is to ensure that users with varying degrees of visual impairment can enlarge the text to meet their needs.

How to Meet

Authors of reflowable EPUB publications need to ensure that they do not define font and container elements in absolute units of measure like pixels. Using flexible measures, like ems and percentages, ensures that when users change font sizes the text remains readable (e.g., it does not overlap nearby elements or get cut off by its bounding element).

This success criterion is typically not an issue for fixed layout EPUBs as reading systems allow users to zoom the content.

Additional Information

The following knowledge base pages provide more information about how to address this success criterion for publishing content:

Text Resizing