| name | readable-line-length |
| description | Use when setting body text column width. 45-65 characters per line is optimal; 75+ causes reading fatigue.
|
Readable Line Length
Optimal reading line: 45-65 characters per line. Max: 75 characters. Below 45 = choppy; above 75 = lose-your-place fatigue.
Width caps by content type
| Content | Width | Characters |
|---|
| Long-form article body | 600-720px | 60-75 |
| News article body | 540-660px | 50-65 |
| Marketing landing body | 600-800px | 60-80 |
| Mobile body | 100% (320-540px) | 30-55 |
| Caption | 540px | 50-65 |
| List items | 480-600px | 45-60 |
Calculation
Characters per line = column width / character width
Inter Tight 16pt: ~7.5px per character
Fraunces 16pt: ~7.8px per character
600px ÷ 7.5 = 80 chars (slightly wide)
540px ÷ 7.5 = 72 chars (good)
Width caps in CSS
.body-prose {
max-width: 70ch;
margin-inline: auto;
}
The ch unit (1 character-wide of the font) is the cleanest way to set readable column.
Where this fits in the X3 empire
Used as body width baseline across CardPrepAI editorial pages.