line-height

Client-by-client behaviour for line-height

Fully supports line-height (19): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman.

Partial support (2): Outlook (New), Outlook Classic. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

When to use line-height in email

• Setting comfortable body-copy leading (typically 1.4–1.6) for readability on small screens.
• Tightening headline leading to keep multi-line titles visually unified.
• Acting as a vertical-spacer trick by setting a large line-height on an empty table cell.

Rendering behaviour and edge cases

• Outlook on Windows uses a different baseline algorithm and can shift text vertically by a pixel or two compared to web browsers.
• Some Android clients scale line-height with user accessibility text-size settings, breaking precise vertical rhythm.
• Setting line-height as a unitless number (e.g. 1.5) is more reliable than fixed px values, as it scales with the inherited font-size.

Recommended fallback strategy

Always pair font-size with an explicit line-height. Prefer unitless values for inherited typography. For pixel-perfect spacer rows, combine an explicit line-height with a height attribute on the <td> to give Outlook a stable vertical baseline.

Fixes & Workarounds