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Email Signature Size Guide: Dimensions & File Sizes
January 30, 2026 6 min read
Marcus Rodriguez
Head of Product & Engineering at Siggly
Getting email signature dimensions right ensures your signature looks professional across all devices and email clients. Here are the recommended sizes.
Recommended Dimensions
| Element | Width | Height |
|---|---|---|
| Overall signature | 300-600px | 150-200px max |
| Company logo | 150-250px | 50-80px |
| Profile photo | 80-100px | 80-100px |
| Social icons | 20-24px | 20-24px |
| Banner/CTA | 400-600px | 70-100px |
File Size Limits
Large images slow down email loading and may be blocked. Follow these guidelines:
- Total signature: Under 50KB combined
- Individual images: Under 20KB each
- Logo: 5-15KB optimal
- Profile photo: 10-20KB
Use PNG for logos with transparency, JPEG for photos. Consider WebP for modern clients, but provide fallbacks.
Mobile Considerations
Over 60% of emails are read on mobile. Your signature should:
- Be readable without zooming (min 12px font)
- Have tappable phone numbers and links
- Not exceed screen width (max 600px)
- Use single-column layout
Retina Display Support
For crisp images on high-DPI screens, create images at 2x the display size:
- 200px display width → 400px actual image
- Set width attribute to display size (200px)
- The browser will scale down for sharpness
Image Format Comparison
| Format | Best For | Support |
|---|---|---|
| PNG | Logos, icons, transparency | Universal |
| JPEG | Photos, complex images | Universal |
| GIF | Simple animations | Most clients |
| SVG | Vector logos | Limited (avoid) |