Gmail vs Outlook Email Signature HTML: What Breaks and Why

Gmail and Outlook use different rendering engines. A signature that looks perfect in one client may show extra gaps, missing fonts, or stripped styles in the other. Design for the lowest common denominator.

CSS that Outlook strips

• Flexbox and grid layouts
• Background images on non-table elements
• Custom web fonts (fallback to Arial/Times)
• Margin collapse on div-based structures

Gmail-specific behavior

• May rewrite some inline styles on paste
• Prefers simple nested tables
• Strips `<style>` blocks in many cases
• Mobile app further simplifies layout

HTML patterns that work in both

• Single outer table, max 600 px width
• Inline styles on every cell
• PNG/JPG images with explicit width/height
• System font stack only

Test before team rollout

Build with compatible templates in our email signature generator — preview catches most issues before export.

Setup guides

Gmail setup · Outlook setup · Common mistakes