The complete guide to email signature size. Ideal dimensions in pixels, image sizes for logos and banners, and formatting rules for Outlook, Gmail, and Apple Mail.
Email Signature Dimensions
Overall Signature Size
| Dimension | Recommended | Maximum |
|---|
| Width | 600px | 700px |
| Height | 150px | 200px |
| Total file size | Under 50KB | 100KB |
Signatures wider than 700px may be clipped or cause horizontal scrolling on mobile devices. Keep the height under 200px — signatures taller than the email body look unprofessional.
Logo Size
| Dimension | Recommended |
|---|
| Width | 100–200px |
| Height | 50–80px |
| File size | Under 30KB |
| Format | PNG (with transparency) |
Profile Photo Size
| Dimension | Recommended |
|---|
| Width × Height | 80–100px square |
| Shape | Circle or rounded square |
| File size | Under 20KB |
| Format | JPG or PNG |
Banner Size
| Dimension | Recommended |
|---|
| Width | 600px |
| Height | 100–150px |
| File size | Under 50KB |
| Format | JPG or PNG |
Social Media Icons
| Dimension | Recommended |
|---|
| Size | 20–24px square |
| Format | PNG with transparency |
| Spacing | 8–12px between icons |
Size by Email Client
Different email clients handle signatures differently:
| Client | Max Width | Image Support | Notes |
|---|
| Gmail | 600px | Good | Clips images wider than 600px on mobile |
| Outlook Desktop | 700px | Good | May block remote images by default |
| Outlook Web | 600px | Good | Signature editor has limited formatting |
| Apple Mail | 700px | Excellent | Most permissive rendering |
| Yahoo Mail | 600px | Good | May add extra spacing |
| Mobile (iOS/Android) | 320–400px | Varies | Always test on mobile |
Image Sizing Best Practices
Retina / High-DPI Displays
Export images at 2x the display size for sharp rendering on retina screens:
- Display at 100px → Export at 200px
- Display at 80px → Export at 160px
- Set the HTML width attribute to the display size
File Size Optimization
Large images slow down email loading and may be blocked:
- Compress images using TinyPNG or Squoosh
- Use JPG for photos (smaller than PNG for photographic images)
- Use PNG for logos (supports transparency, sharper for graphics)
- Avoid BMP and TIFF — not supported in most email clients
Image Hosting
- Hosted images (URL) — smaller email size, but may be blocked by default
- Embedded images (inline/base64) — always visible, but increases email size
- TooStamply generates signatures with inline images for maximum compatibility
Email Signature Size in Physical Units
If you're designing in Photoshop, Illustrator, or Canva:
| Pixels | Inches (72 DPI) | Centimeters |
|---|
| 600px wide | 8.33 inches | 21.2 cm |
| 150px tall | 2.08 inches | 5.3 cm |
| 100px (logo) | 1.39 inches | 3.5 cm |
| 80px (photo) | 1.11 inches | 2.8 cm |
Important: Always design in pixels, not inches. Email clients render in pixels regardless of DPI settings.
Common Size Mistakes
- Logo too large — Dominates the signature, looks like an advertisement
- Too many lines of text — Keep to 3–5 lines: name, title, company, phone, website
- Banner too tall — Makes the signature longer than the email content
- Social icons too big — 20–24px is sufficient; larger icons look cluttered
- No mobile testing — Always send a test email and check on your phone
Related Guides
Create a perfectly sized email signature →
Frequently Asked Questions
What is the ideal email signature size?
The ideal email signature is 600–700px wide and 150–200px tall. This ensures it displays correctly across desktop and mobile email clients without scrolling or clipping.
What size should an email signature image be?
Logo: 100–200px wide, max 80px tall. Banner: 600px wide, 100–150px tall. Profile photo: 80–100px square. Keep all images under 50KB for fast loading.
What is the best image format for email signatures?
PNG for logos with transparency, JPG for photos and banners. Avoid SVG (not supported in most email clients) and GIF (large file size, blocked by some clients).
Why does my email signature image look blurry?
Export images at 2x the display size (e.g., 200px image displayed at 100px) for retina/high-DPI screens. Also ensure you are using PNG format for logos, not JPG.