Justified text is text that is spaced so that the right and left sides of the paragraph have the same edge. In other words, the text block is aligned with both margins of the page.
It’s unusual on the internet, but common in printed newspapers and some older books. Most English-language websites use left-aligned text, which aligns each paragraph with — you guessed it — the left margin.
However, some designers use justified text for effect. Text justification can be visually appealing in some circumstances, but it can also create issues for people with dyslexia, low vision, and other disabilities. Here’s why.
Text justification makes long blocks of text less readable
The layout of your text affects its readability. If text is fully justified or center-justified, people may have issues with tracking (finding the beginning of each line of text).
This is true for every user, not just individuals with disabilities. Try reading an older newspaper that uses fully justified text (the website of the U.S. Library of Congress has an archive of newspapers dating back to the 1690s). You might find yourself skipping lines or missing words — and that isn’t surprising, since most modern readers are more comfortable with left-aligned text.
Why? For starters, fully justified text introduces blank space between characters or between words. This allows the text to appear as a single block with perfect margins, but it also creates inconsistent spacing, which can force the reader’s eyes to “jump" when reading.
This becomes a serious issue when using assistive technologies (AT). Many people with vision disabilities use screen magnifiers or enlarge web content by “zooming in" on the page. If text is justified, these users may see large, empty spaces between (or within) words — or the words may run together in a confusing mess of characters.
Center-justified text is less problematic than fully justified text, but it can still be difficult to read (and may still cause issues when the text is magnified).
WCAG recommends avoiding text justification
When discussing accessibility issues, it’s a good idea to reference the Web Content Accessibility Guidelines (WCAG), the international standards for digital accessibility.
WCAG is published by the World Wide Web Consortium (W3C), which also maintains the standards for HTML (HyperText Markup Language) and CSS (Cascading Style Sheets).
By default, CSS uses left justification for left-to-right scripts (such as English) and right justification for right-to-left scripts (such as Arabic).
Per the W3C’s supplemental guidance on text justification, designers should stick with the defaults unless they have a very good reason to do otherwise. You can justify text via the CSS text-align property, but this isn’t a great idea for longer blocks of text.
Here are some basic rules to keep in mind when determining text layout:
Avoid using full text justification.
Avoid using center justification (“centering" text) for text blocks that are longer than 1-2 lines.
If you must use center justification, try to provide users with a mechanism for changing the justification.
Make sure that your content does not lose information or functionality when users change the text justification.
By following these tips, you’re fulfilling part of the requirements of WCAG Success Criterion 1.4.8, “Visual Presentation,” which also includes requirements for line spacing and text-block width.
This criterion is a Level AAA requirement, which means that it’s not strictly necessary for most websites — but as we’ve discussed in other articles, WCAG Level AAA success criteria are still worth your attention.
Think about your audience when making web design decisions
For most websites, text justification isn’t a major concern, but it highlights the importance of considering the needs and expectations of all users when designing your content.
When creating your website, you should also consider color contrast ratios, font choices, and the ways you use color to convey meaning. Test your designs against WCAG, and before making each decision, think about how it may affect users with disabilities.
By prioritizing accessibility, you’ll provide all users with better experiences — and keep them engaged with your content. For additional guidance, read our free eBook: Developing the Accessibility Mindset.