The best font for email marketing is the one that displays correctly everywhere your campaign lands. Email clients have very limited support for custom (web) fonts, so the safest choice is a “web-safe” system font — available on every operating system — with a sensible fallback stack.
Web-safe fonts that work everywhere
For sans-serif body text, the safest options are Arial or Helvetica (maximum compatibility), Verdana (excellent for long blocks of text), Tahoma (compact UI text) and Trebuchet MS (a friendly, modern feel). For a more editorial tone, Georgia and Times New Roman are reliable serifs. Courier New is the safe pick for code, receipts or any fixed-width content.
Web fonts and Outlook
Google Fonts and other web fonts work on Apple Mail, the Gmail web app and most modern clients. Outlook on Windows ignores them and falls back to Times New Roman by default. Always pair a web font with a web-safe fallback so the email looks reasonable everywhere.
Size, line-height and contrast
Use 14–16 px for body text on desktop, never below 12 px on mobile, and a line-height around 1.4–1.6. Keep contrast strong (dark text on light background) and limit yourself to two type sizes per block to keep things scannable. See good email design for the full layout checklist.
Pick one font and stick to it
Set a body font + fallback in your Mailpro template once, then re-use it across every campaign. Pair it with a strong subject line for maximum impact.