Line Length

How many characters sit on one line of text, also called the measure. Around 45 to 75 characters reads comfortably; much longer and the eye loses its place on the way back to the start of the next line.

Why it matters

On a long line the return sweep gets unreliable — the eye drops back and lands on the line it just read, or skips one entirely. It reads as tiring without the reason being obvious.

The numbers

• 45-75 characters — the comfortable measure
• Roughly 600px at 16px body type

Measured by the Figma plugin

Fixed-width text running well past 75 characters per line is flagged with its estimated measure.

Put the coach in your canvas

Related terms

• Line Height
• F-Shape
• Typeface
• Alt Text
• Baseline Grid

On the checklists

• Design System Checklist Typography

Ask your assistant

Define "Line Length" using uxspot.

Works in Claude, Cursor or any MCP client — connect the uxspot MCP.

Think it stuck? A 20-second round of Spot Check will tell you.