Email Signature Size Guide: Width, Height, Fonts and Logo Dimensions
The exact numbers for a signature that fits every screen, from a wide desktop to a small phone.
By Engineering Team, Engineers, Gas Alley Studios · Updated 2026-10-12 · 5 min
Recommended email signature dimensions: overall width, height, logo and photo sizes, and font sizes that stay readable in every email app.
Overall width and height
Keep the whole signature at or under 600px wide — the standard width for email content — and ideally around 450–500px. Many phones show about 360px of width, so anything wider forces sideways scrolling or gets shrunk until it is unreadable.
Aim for a height of roughly 100–180px. Taller signatures dominate short replies and push the conversation off screen in threads.
Logo and photo sizes
Logo: about 100–150px wide and no more than about 80px tall when displayed. Export the file at twice that size for sharp results on high-resolution screens, and set the display width in the code.
Headshot: 60–90px square or round. Smaller photos read as icons; larger ones feel like a dating profile.
Social icons: 16–24px each, with a few pixels of space between them. Keep the files small — under about 50KB per image — so the signature loads quickly.
Font sizes
Name: 16–18px, bold. Title and company: 13–14px. Contact details: 13–14px. Legal disclaimers: 11–12px at the very smallest. Always set sizes in pixels, because relative sizes are interpreted differently from app to app.
Line height: about 1.4–1.5 times the font size, written as a fixed pixel value (for example 20px for 14px text). The style guide explains the extra setting Outlook needs to respect it.
Put these tips into practice
Gas Alley Studios engineers build the SignatureCraft editor and export pipeline, and spend an unreasonable amount of time inside Outlook 2016 debugging table layouts.