Font size gets most of the attention, but line length matters just as much. Lines that stretch across a wide screen are tiring to read. Your eyes have to travel too far, and when they jump back to the left, it’s easy to lose your place.
The ideal line length. Typographers have long recommended around 50 to 60 characters per line, including spaces. This guideline goes back to classic print typography, including the Swiss designer Emil Ruder’s influential book Typographie. On the web, many designers allow a slightly wider range, up to around 75 characters.
It’s hard to picture 50 to 60 characters without counting. In everyday English, that works out to roughly 9 to 11 words per line. In practice, a text column of around 600 to 700 pixels wide, with 16 to 18 pixel type, lands close to this range.
People prefer shorter lines. Researchers studying on-screen reading, including the team of de Bruijn and colleagues, found that readers tend to prefer shorter line lengths because the text looks more organized and easier to take in. Generous spacing between lines helps too. When lines sit too close together, the eye struggles to follow from one line to the next.
This is why so many well-designed blogs and news sites keep their article text in a fairly narrow central column, even on very wide screens. The empty space on either side isn’t wasted. It’s what makes the text comfortable to read.
Design for your actual readers. A 16-pixel font is easy for most people to read, but think carefully about your audience. The World Health Organization estimates that more than two billion people worldwide live with some form of vision impairment. Eyesight also changes naturally with age, and most people begin to need reading glasses in their 40s.
Is your audience over or under 40? If you serve an older market, bigger is better: consider 18-pixel body text, generous line spacing, and strong contrast between text and background. These choices don’t just help people with weaker eyesight. They make reading easier for everyone.
A quick test. Pick a paragraph on your website and count the characters in a typical line. If it’s well over 80, narrow your text column. If it’s under 40, your column may be too narrow, causing awkward breaks and choppy reading.
