Why text width of 50 to 80 characters matters for UX and accessibility

By Anne-Mieke Bovelett on November 18, 2025
Status: up to date

Ultimately, wide boxes of text affect your conversion

Think of reading text like mowing a lawn. A narrow lawn strip is easy to mow in a straight line, turn around, and do the next strip. A strip that is 30 meters wide? By the time you reach the end, you have no idea where you started the return pass. Your eyes work the same way.

What your eyes actually do

Reading is not a smooth glide across the page. Your eyes make rapid jumps from word to word (called saccades), pause briefly to process text (called fixations), then sweep back to the start of the next line. When a line exceeds about 80 characters, that return sweep overshoots. Readers skip a line or read the same line twice. During the sweep back, your brain briefly suppresses vision so you do not perceive a blur, and the longer the line, the longer that visual blackout lasts.

Who is most affected

Long lines are tiring for everyone, but they cause genuine barriers for specific groups:

People with some cognitive, language and learning disabilities, and some low vision users, cannot perceive the text and lose their reading place if text is presented in a manner that is difficult for them to read. And if “disabilities” sounds like a vague term to you. At least 10% of your audience has a form of dyslexia, ADHD, ASD, and a very large percentage of your visitors are having trouble simply because they are tired, rushing, agitated, and some are simply old.

People with some cognitive disabilities find it difficult to track text where the lines are close together. Having a narrow block of text makes it easier for them to continue on to the next line in a block.

What is also affected…

Your conversions. Make something difficult to read, and people jump ship. It’s as simple as that. I have published an extensive article about customer experience with hard numbers.

The official standard

This is covered in WCAG 2.2 Success Criterion 1.4.8: Visual Presentation (Level AAA). The requirement states that width is no more than 80 characters or glyphs, or 40 if the content is in Chinese, Japanese, or Korean (CJK), since those characters are approximately twice as wide visually.

Worth noting: 1.4.8 is Level AAA, so it is not required for most compliance targets. But the sweet spot of 50 to 75 characters is widely recommended as the practical optimum for body text, with 80 as the hard ceiling. Also by UX experts. You don’t just want to be compliant, you want your pages to convert, right? Making sure that your texts are always at level AAA is a smart business move.

How to implement it in CSS

Here is the beginner-friendly version. Think of ch as a unit that roughly equals “the width of one character” in your current font:

.article-body {
  max-width: 70ch;
}

Setting max-width: 70ch tells the browser: “never let this text container grow wider than about 70 characters.” Even though WCAG allows up to 80, using 70 instead leaves a little breathing room for things like padding, margins, or slight font differences.

Official sources

W3C Low Vision Accessibility Task Force: Line Length — the working group background and rationale

WCAG 2.2 Understanding SC 1.4.8: Visual Presentation — W3C/WAI

WebAIM WCAG 2 Checklist — practical checklist with line length included