usability.cat

Typography

Font choices, sizing, and hierarchy that make your content readable.

Typography is the single biggest factor in whether your site feels professional or amateur. Good news: the rules are simple.

Font size

The most common mistake is text that's too small.

Readable body text
  • Body text: 16px or larger - Small text (captions): 14px minimum - Never go below 12px for anything
Squinting required
  • Body text at 13px or 14px - Captions at 10px or 11px - Users pinching to zoom on mobile
High impactreadability~2 paws

Body text below 16px drops readability scores significantly. This is one of the easiest fixes.

Heading hierarchy

Headings should form a clear visual ladder. Each level should be noticeably different.

Clear hierarchy
  • h1: 36-48px, bold — page title - h2: 28-32px, bold — main sections - h3: 20-24px, semibold — subsections - Body: 16-18px, regular
Everything looks the same
  • h1 and h2 are the same size - h3 is barely different from body text - No visual distinction between levels

Rule of thumb: Each heading level should be at least 1.25x the size of the next level down.

Line height (leading)

Line height is the space between lines of text. Too tight and text feels cramped. Too loose and it falls apart.

Comfortable reading
  • Body text: line-height of 1.5 to 1.7 - Headings: line-height of 1.1 to 1.3 - Short labels: line-height of 1 to 1.2
Cramped or floaty
  • Body text with line-height of 1.0 (lines touching) - Or line-height of 2.5 (text floating apart)

Line length

Long lines of text are hard to read. Your eyes lose track of which line comes next.

Easy to follow
  • 50-75 characters per line - Max container width of ~700px for text content - Paragraphs feel natural to read
Full-width text wall
  • Text stretching edge to edge on wide screens - 120+ characters per line - Eyes get lost moving to the next line
Medium impactreadability~1 paw

Extremely long line lengths hurt readability scores. Wrap text content in a max-width container.

Font choice

Stick to well-known, web-safe fonts. Fancy fonts are usually harder to read.

Clean and readable
  • System fonts (Inter, Geist, Noto Sans) - One font family for body, one for headings (max 2) - Consistent weight usage (regular + bold)
Font chaos
  • 4+ different font families - Decorative fonts for body text - Inconsistent weights across the page

Quick checklist

Self-assessment checklist

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