For readable body text, a good target is 45–75 characters per line , including spaces; around 66 characters is often cited as ideal. For web/mobile layouts, staying near 50–75 usually works best.

Practical ranges

  • Body text: 45–75 characters per line.
  • Ideal sweet spot: about 66 characters.
  • Code or technical text: many style guides use 79–100 or 80 characters, depending on the language or guide.

Why it matters

Short lines can feel choppy and force too many line breaks, while very long lines make it harder for the eye to track back to the next line. That’s why most typography guidance lands in the mid-range rather than at an extreme.

Simple rule

If you are setting paragraph text, aim for about 60–70 characters per line and adjust slightly for font size, screen width, and language.

TL;DR: Aim for 45–75 characters per line, with roughly 66 as a strong default.