What is the recommended line length and line-height for comfortable reading in UI typography?

• A. Very short line length with tight line-height.
• B. Extremely long lines with low line-height.
• C. Line length of 45-75 characters with appropriate line-height.
• D. Any length; line-height is unrelated.

Answer: (C)

Readable UI typography relies on balancing how long a line sits on the screen with how much vertical space sits between lines. Aim for a line length around 45 to 75 characters per line; this range keeps the eye from jumping too far to the next line while still allowing a comfortable amount of text to appear before a wrap. Pair that with a line height that gives ample breathing room—about 1.4 to 1.6 times the font size—so lines aren’t cramped and the text flows smoothly from one line to the next. On smaller screens, shorter lines help maintain this rhythm, but the principle remains: lines shouldn’t be too long or too tight, and the vertical spacing should be enough to guide the eye. Together, these settings create readable, comfortable body text in UI typography.