Spacing rules

SF fonts use automatic tracking — the space between letters changes based on text size. This system creates optimal spacing without manual adjustments from designers.

The tracking system follows a precise pattern:

• 12pt text has 0 tracking as a baseline
• 10pt text gets +12 tracking (1/1000 em)
• 13pt text receives -6 tracking
• 17pt text uses -26 tracking
• 28pt text returns to +14 tracking

These adjustments happen automatically in Apple interfaces. For example, notice how footnotes at 10pt get more space between letters for better readability, while headlines at 17pt use tighter spacing to create stronger visual impact.

The tracking system works across SF variants. Whether using SF Pro in Mail or SF Compact on Apple Watch, text maintains proper spacing based on its size. This creates a consistent reading rhythm across all Apple platforms.