What is the Optimal Text Length Per Line on Websites?

When it comes to website design, every detail counts and that includes something as simple small as the length of each line of text. It might not be the first thing you think about when designing a web page, but line length has a major impact on how users read, absorb, and engage with your content.

So, what exactly is the optimal line length for websites? And why does it matter so much?

Let’s break it down in this blog post.

Why Line Length Matters in Web Design

Reading on a screen isn’t the same as reading a book. On websites, users typically scan content rather than reading word-for-word. That means designers and content strategists need to present information in a way that supports readability and focus. 

This is exactly the main reason why line length is important.

Too short, and your text feels choppy. Too long, and it becomes difficult for users to track the start of the next line. In both cases, readability and comprehension take a hit, and users are more likely to bounce.

The Science Behind Optimal Line Length

Research in both web usability and traditional typography has long pointed to an ideal range for line length. Most experts agree that 50 to 75 characters per line (including spaces) is the sweet spot for comfortable reading.

This range strikes a balance: long enough to avoid frequent eye movement back and forth, but short enough to maintain flow and focus. It supports how the human eye scans content in horizontal sweeps known as saccades, followed by brief pauses to process text.

Jakob Nielsen, a pioneer in UX research, even found that users read faster with moderately long lines but prefer the appearance of shorter ones. In essence, people want it to feel readable and be efficient at the same time.

How Line Length Affects User Behavior

Let’s consider two options:

• Long lines (over 100 characters) require more horizontal eye movement and make it harder to locate the start of the next line. This slows reading speed and increases fatigue.
• Short lines (under 40 characters) break the rhythm of reading. The eye is forced to jump down more frequently, which disrupts comprehension.

When users struggle to read, they tend to skim which means they don’t get to consume the most important information. It could be your CTAs, your unique value proposition, or the services you offer. Or worse, they can leave the page entirely. As a result, this could mean lower engagement, decreased trust, and lost conversions.

How to Design for Optimal Line Length

Imagine reading a paragraph that stretches across a full-width desktop screen. Now compare that to the column of text in a newspaper or a blog which tends to be narrower. The latter feels easier, right?

Now, achieving the perfect line length isn’t that complicated. But what you want to remember that it’s all about smart, responsive design. Here are a few tips:

• Use CSS max-width: This limits how wide text containers can stretch, especially on larger screens.
• Choose appropriate font sizes: A larger font naturally shortens line length, but too large can overwhelm the layout. Aim for 16px–18px for body text.
• Set a suitable line height: Around 1.5 to 1.6x the font size is usually ideal for readability.
• Use padding and margins wisely: Adding horizontal padding inside text containers can help control readability without altering layout too dramatically. 
• Consider column-based layouts: For content-heavy pages, breaking up text into two or three columns on wider screens can preserve optimal line lengths and improve scanning.
• Avoid full-justified text: While it may look neat, fully justified text can create uneven spacing between words, especially with longer lines.
• Test with real content: Dummy text can mislead you. Always test your layout with actual content to ensure line length and flow work well together.
• Apply responsive breakpoints: Ensure text doesn’t become too wide or too narrow across devices by using media queries.

For example, setting:

.container {

  max-width: 700px;

  margin: 0 auto;

}

…creates a readable, centered block of text that generally falls within the optimal 50–75 character range (depending on font). 

Helpful Tools for Designers and Developers

Want to test your own site? Here are a few tools and tips:

• Browser Dev Tools: Use the inspector to check container widths and font sizes.
• Character Count Extensions: Add-ons like “Text Inspector” can show real-time character counts per line.
• Design Systems: Google’s Material Design and Bootstrap offer responsive typographic defaults that promote good readability.

Conclusion

The optimal text line length on websites isn’t just a design detail — it’s a usability essential. Staying within the 50–75 character range helps readers stay focused, improves comprehension, and enhances the overall experience of your site.

At Chromatix, we specialise in human-first web design that’s grounded in usability. That’s why, we’ve seen firsthand how small changes in content formatting, like adjusting line length, can improve time on site and readability metrics in website heatmaps and analytics. It’s a subtle, but powerful, design lever.

Give us a call today to start turning browsers into buyers, one readable line at a time.