Line length is the amount of text, commonly measured in characters, spanning one line. For readable web copy, aim for roughly 45–70 characters per line. Shorter lines support scanning, while longer lines make sustained focus harder. section 8.2.6
Apply line length as a practical layout decision:
- Limit the width of text columns or set a max-width on headings and paragraphs. section 8.2.6
- Check line length alongside line height, since both influence readability, especially in large blocks of text. section 10.5
- Test the result with users or several readers rather than treating the character range as an inflexible rule. section 8.2.6
A readable text column
When building a webpage, constrain a paragraph or heading so its lines stay near the 45–70-character range, then review the result with the chosen typeface and line height. section 8.2.6 section 10.5
