Across most industries, 55-65% of email opens happen on a mobile device. Designing your email for desktop first and hoping it works on mobile is designing for the minority of your audience.
This Week’s Lesson
Mobile-first email design means you design the mobile layout first, then adapt for desktop — not the reverse. This means: single column layout, larger font sizes, generous tap targets, minimal content.
Font size: minimum 14px for body text, 18-20px for headings on mobile. Anything smaller forces users to pinch-and-zoom, which they won't do — they'll delete the email.
Tap targets: buttons and links should be at least 44×44 pixels. Fingers are less precise than mouse cursors. Tiny links clustered together create accidental taps and frustration.
Single-column vs. multi-column: multi-column layouts often collapse poorly on mobile. A two-column product grid that looks great on desktop can render as a jumbled mess on a 375px screen if not properly coded with media queries.
Image optimization: large images slow load times on mobile networks. Compress images, use modern formats like WebP, and always include ALT text — many mobile users have images disabled by default.
Testing: use a tool like Litmus or Email on Acid to preview your email across 100+ email clients and device sizes before sending. A single broken template seen by 60% of your audience in mobile is a significant deliverability and engagement problem.