Line Length Calculator

Optimal characters per line from size and width.

Font size (px)

Container width (px)

Avg char width (em)

Side padding (px)

Tab to move between fields

Characters per line

Words per line14.2

Readability rating50/100

Ideal container width (px)528

Min comfortable width (px)360

Max comfortable width (px)600

How to Use This Calculator

How the result changes with Font size (px)

Font size (px): Body text font size in pixels.
Container width (px): Width of the text container or column in pixels.
Avg char width (em): Average character width as fraction of font size. Sans serif ≈ 0.50, serif ≈ 0.45, condensed ≈ 0.38, monospace ≈ 0.60.
Side padding (px): Horizontal padding on each side of the container.

Characters per line: Estimated characters per line. Optimal range: 45–75 (Bringhurst). Ideal: ~66.
Words per line: Approximate words per line (avg English word = 5 chars + space).
Readability rating: Score based on how close your measure is to the optimal 45–75 character range.
Ideal container width (px): Container width that yields ~66 characters per line at your font size.
Min comfortable width (px): Container width for 45 characters per line (minimum comfortable).
Max comfortable width (px): Container width for 75 characters per line (maximum comfortable).

Identify Input Parameters
4 parameters
Font size (px) = 16, Container width (px) = 680, Avg char width (em) = 0.5, Side padding (px) = 0 = 4 input(s) provided
Calculate Characters per line
85 = 85
Calculate Words per line
Words per line = charsPerLine / 6
14.2 = 14.2
Calculate Readability rating
Readability rating = Math
50 = 50