Email Signature Dimensions: The Complete Size Guide for Every Element

Email signature dimensions are the pixel width, height, and file size specifications for each visual element in your email sign-off block. The standard recommended overall width is 600 pixels or less, with a total height between 150 and 200 pixels, ensuring your signature displays correctly across all major email clients and devices.

Getting dimensions wrong is one of the fastest ways to make a professional email look broken. Oversized images push content off-screen. Tiny logos become unreadable smudges. Banners that look crisp on your desktop turn into blurry rectangles on a phone. These problems are entirely preventable when you know the correct pixel specifications for each element.

This guide covers every dimension you need, from overall signature size to individual elements like logos, headshots, banners, and social icons. You will also find client-specific comparison tables, mobile rendering considerations, and file format recommendations.

Why Email Signature Dimensions Matter

Rendering Consistency Across Clients

Email clients do not share a single rendering engine. Outlook uses Microsoft Word's rendering engine. Gmail strips certain CSS properties. Apple Mail is the most forgiving but still has limits. Each client interprets image dimensions differently, which means a signature that looks perfect in one inbox can break in another.

According to Litmus, over 90% of email opens occur across just five email clients: Apple Mail, Gmail, Outlook, Yahoo Mail, and Samsung Mail (Litmus Email Client Market Share, 2025). If your signature dimensions work well in these five clients, you cover the vast majority of your recipients.

Deliverability and Load Speed

Large image files trigger spam filters and slow down email loading. Email security gateways flag messages with oversized attachments or embedded images. When your total signature image weight exceeds 100KB, you risk deliverability issues and frustrated recipients waiting for images to load.

Mobile-First Reality

More than half of all emails are opened on mobile devices. A signature designed only for desktop widths will either overflow the screen or get compressed in unpredictable ways. Designing with mobile dimensions in mind from the start prevents these problems entirely.

Recommended Overall Signature Dimensions

The overall signature container sets the boundaries for everything inside it. Get this wrong and every individual element inherits the problem.

Width

The ideal email signature width is between 500 and 600 pixels. This range fits comfortably within the reading pane of every major email client on both desktop and mobile.

Why 600px is the ceiling:

Gmail's compose window defaults to roughly 640px wide
Outlook's reading pane is typically 600-700px
Mobile screens in portrait mode are 320-414px (CSS pixels), so anything wider than 600px forces horizontal scrolling
Most email templates use 600px as the standard content width

Height

Keep total signature height between 150 and 200 pixels. Some clients (notably Outlook) collapse signatures visually when they exceed a certain height, and recipients rarely scroll past the first fold of a message.

Overall Signature Size Specifications

Specification	Recommended Value
Maximum width	600px
Ideal width	500-600px
Maximum height	200px
Ideal height	150-200px
Total image weight	Under 100KB combined
Number of images	3-5 maximum

Logo Dimensions

Your company logo is typically the most prominent image in a signature. It needs to be large enough to be recognizable but small enough to stay in proportion with the rest of the layout.

Recommended Logo Sizes

Specification	Recommended Value
Display width	150-300px
Display height	30-80px
Source file width	300-600px (2x for retina)
Source file height	60-160px (2x for retina)
Maximum file size	50KB
Aspect ratio	Maintain original

The optimal email signature logo width is 150 to 300 pixels at display size, with a source file exported at 2x resolution (300 to 600 pixels) so it renders sharply on high-DPI screens like Retina displays.

A few things to keep in mind:

Horizontal logos work better than square or vertical ones in signatures
If your logo is square (like an app icon), limit display height to 60px
Always set explicit width and height attributes on the <img> tag to prevent layout shifts while the image loads

For a deeper look at logo placement, formats, and hosting, see our complete email signature logo guide.

Headshot and Photo Dimensions

A headshot adds a personal touch and builds trust with recipients. The key is keeping the photo large enough to be recognizable without dominating the signature layout.

Recommended Photo Sizes

Specification	Recommended Value
Display size	80x80px to 120x120px
Source file size	160x160px to 240x240px (2x)
Shape	Square or circular crop
Maximum file size	30KB
Format	JPG (photos) or PNG (with transparency for circular crop)

For most layouts, an 80x80px to 100x100px display size hits the right balance. The photo is large enough to be recognizable but compact enough to sit beside your contact details without pushing the signature height beyond 200px.

A professional headshot in your email signature should be 80 to 120 pixels square at display size, with a 2x resolution source file for sharp rendering on high-DPI screens, and compressed to under 30KB.

If you use a circular crop, export the image as PNG with transparency rather than placing a white circle mask over a JPG. This approach ensures the crop looks correct regardless of the recipient's email background color. Learn more in our guide to email signature photos.

Banner Dimensions

Campaign banners (sometimes called promotional banners or CTA banners) sit below the main signature block and link to a landing page, event, or promotion. They are one of the most effective marketing tools hidden in plain sight.

Recommended Banner Sizes

Specification	Recommended Value
Display width	500-600px
Display height	80-120px
Source file width	1000-1200px (2x)
Source file height	160-240px (2x)
Maximum file size	50KB
Aspect ratio	5:1 to 6:1

The recommended email signature banner size is 600 pixels wide by 100 pixels tall at display resolution, matching the overall signature width for visual alignment.

Banners should span the full width of the signature to create a clean, professional look. Avoid making them taller than 120px at display size because a tall banner makes the entire signature feel heavy and is more likely to be clipped by email clients that collapse long messages.

For banner design inspiration and templates, check out our email signature banner templates.

Social Media Icon Dimensions

Social media icons are small, but incorrect sizing makes them look blurry or misaligned. Consistency across all icons is more important than the exact pixel count.

Recommended Icon Sizes

Specification	Recommended Value
Display size	20x20px to 24x24px
Source file size	40x40px to 48x48px (2x)
Maximum file size	5KB per icon
Spacing between icons	8-12px
Maximum number of icons	4-6
Format	PNG (with transparency)

Keep all icons the same size. Mixing a 20px LinkedIn icon with a 24px Twitter icon creates visual noise that is immediately noticeable. Use the same icon style (outlined, filled, or monochrome) for all social links.

Each social media icon in your email signature should be exactly 20 to 24 pixels square at display size, with a consistent style and uniform spacing of 8 to 12 pixels between each icon.

Email Client Dimension Comparison Table

Different email clients handle images and overall signature dimensions in different ways. This table summarizes the key differences you need to know.

Maximum Supported Dimensions by Client

Feature	Gmail	Outlook (Desktop)	Apple Mail	Yahoo Mail	Thunderbird
Max signature width	600px (recommended)	600px (Word engine)	No hard limit	600px (recommended)	No hard limit
Max signature height	No hard limit (clips at ~102KB of HTML)	~1000px before collapse	No hard limit	No hard limit	No hard limit
Retina/HiDPI support	Yes	Partial (desktop app)	Yes	Yes	Yes
SVG support	No	No	Yes	No	Yes
GIF animation	Yes	Limited (first frame in some versions)	Yes	Yes	Yes
Image blocking default	Images shown	Images blocked (first open)	Images shown	Images shown	Images blocked
Max total email size	25MB	20MB (Exchange) / 25MB	20MB	25MB	No hard limit
Background images	Partial	VML fallback needed	Yes	No	Yes

Key Takeaways from the Comparison

Outlook is the most restrictive client. It blocks images by default on first interaction, ignores SVG, and uses Word's rendering engine, which means your signature HTML must use table-based layouts with inline CSS. Gmail is moderately permissive but clips long emails after roughly 102KB of HTML.

Apple Mail and Thunderbird are the most lenient, but you should never design solely for the most forgiving client. Always design your email signature dimensions for the most restrictive client your audience uses, then verify it works everywhere else.

Mobile vs. Desktop Rendering Differences

Screen Width

Desktop email clients typically show signatures in a reading pane between 600 and 800 pixels wide. Mobile screens in portrait orientation are 320 to 414 CSS pixels wide. A 600px wide signature will scale down on mobile, which means all text and images shrink proportionally.

What This Means for Your Dimensions

Logos below 150px display width become difficult to read on mobile after scaling
Social icons below 20px become nearly impossible to tap accurately (Apple's Human Interface Guidelines recommend a minimum 44x44px tap target, so spacing around small icons matters)
Banners render well on mobile as long as text within the banner is large enough to remain legible at 50% of the original size
Headshots at 80px or larger maintain clarity after mobile scaling

Testing Mobile Dimensions

Send a test email to yourself and open it on your phone. Check specifically for:

Is the logo still readable?
Can you tap each social icon without accidentally hitting the wrong one?
Is the banner text legible without zooming?
Does the overall layout still make sense at the narrower width?

DPI and Resolution Considerations

The Retina Problem

High-DPI screens (Apple Retina, most modern Android devices, and many Windows laptops) display at 2x or 3x the standard pixel density. An image saved at 100x100px looks fine on a standard screen but appears blurry on a Retina display because the screen has twice as many physical pixels to fill.

The 2x Export Rule

Export all email signature images at 2x your intended display size, then set the display dimensions using HTML width and height attributes. For example, if your logo displays at 200x50px, export the source file at 400x100px.

Element	Display Size	Source File Size (2x)
Logo	200x50px	400x100px
Headshot	100x100px	200x200px
Banner	600x100px	1200x200px
Social icon	24x24px	48x48px

This approach keeps images sharp on Retina screens while controlling the display size through HTML attributes. Most email clients respect the width and height attributes on <img> tags, which prevents the full-resolution image from expanding beyond its intended display area.

When 3x Matters

Some newer devices run at 3x density. For most email signatures, 2x is sufficient because the viewing distance for email is typically further than for mobile app interfaces. The file size increase from 2x to 3x is significant and rarely justified for signature elements.

File Format Recommendations

PNG

Best for: logos, icons, images with transparency, graphics with sharp edges or text.

PNG supports transparency, which is essential for logos on varied email backgrounds and circular headshot crops. The downside is larger file sizes compared to JPG for photographic content. Use PNG-8 (256 colors) for simple graphics and PNG-24 for images needing full color depth.

JPG

Best for: headshots, photographs, banners with photographic backgrounds.

JPG compression excels at reducing file size for photographic content. Export at 80% quality for the best balance between visual clarity and file weight. Avoid JPG for graphics with text or sharp edges because compression artifacts become visible.

SVG

Best avoided in email signatures. While SVG files are resolution-independent and tiny in file size, Gmail and Outlook (the two most-used email clients for business) do not render SVG in email. Apple Mail and Thunderbird support SVG, but the inconsistency makes it unreliable.

GIF

Use only for animated elements like a subtle logo animation. Keep animated GIFs under 30KB and limit to 3-5 frames. Note that Outlook displays only the first frame of animated GIFs in some versions, so your first frame should look complete on its own.

Format Summary

Format	Transparency	Animation	Email Client Support	Best For
PNG	Yes	No	Universal	Logos, icons, graphics
JPG	No	No	Universal	Photos, banners
SVG	Yes	Yes	Limited (no Gmail/Outlook)	Avoid in signatures
GIF	Yes	Yes	Universal (static fallback in some Outlook)	Simple animations only
WebP	Yes	Yes	Limited (no Outlook)	Avoid in signatures

Common Sizing Mistakes and How to Fix Them

Mistake 1: Using Full-Resolution Images Without HTML Sizing

Uploading a 1200x400px logo and relying on the email client to scale it down is unreliable. Some clients will display it at full size, pushing your signature off-screen.

Fix: Always set width and height attributes on every <img> tag. Export at 2x but display at 1x using HTML attributes.

Mistake 2: Inconsistent Icon Sizes

Grabbing social icons from different sources results in mismatched dimensions. A 32px LinkedIn icon next to a 20px Twitter icon looks unpolished.

Fix: Download or create all icons from a single icon set at the same dimensions. Export them all at the same pixel size (e.g., 48x48px source, 24x24px display).

Mistake 3: Banners That Are Too Tall

A banner taller than 120px makes the signature feel like a second email rather than a sign-off. Recipients are less likely to engage with it, and email clients may clip it.

Fix: Keep banner display height at 80-100px. Use horizontal layouts with large text rather than stacking multiple lines vertically.

Mistake 4: Ignoring File Size

Beautiful images mean nothing if they add 500KB to every email. Large attachments trigger spam filters, slow loading, and consume recipients' data.

Fix: Compress all images before embedding. Use tools like TinyPNG, ImageOptim, or Squoosh. Aim for these targets:

Logo: under 50KB
Headshot: under 30KB
Banner: under 50KB
Each icon: under 5KB
Total signature images: under 100KB

Mistake 5: Not Testing on Mobile

A signature designed at 600px wide on a desktop monitor may have text that becomes unreadable after mobile scaling.

Fix: Send test emails to your phone. Check every element for readability and tap accuracy. Increase font sizes or icon spacing if anything is too small.

How to Test Dimensions Across Email Clients

Manual Testing

The simplest approach is to send test emails to accounts on each major client:

Gmail (personal Gmail or Google Workspace)
Outlook (Outlook.com or desktop app)
Apple Mail (any iCloud or configured account)
Yahoo Mail (free account works)
Mobile (iOS Mail and Gmail app)

Open each test email and verify: overall width fits without horizontal scrolling, images are sharp, icons are evenly sized, and no elements are cropped or misaligned.

Email Preview Tools

For more thorough testing, use dedicated preview tools:

Litmus provides screenshots across 90+ email clients and devices
Email on Acid offers similar preview functionality with a focus on Outlook rendering
Mailtrap lets you inspect the raw HTML and preview rendering

Checklist for Testing

Quick Reference: All Dimensions in One Table

Element	Display Width	Display Height	Source Width (2x)	Source Height (2x)	Max File Size
Overall signature	500-600px	150-200px	N/A	N/A	100KB total
Logo	150-300px	30-80px	300-600px	60-160px	50KB
Headshot	80-120px	80-120px	160-240px	160-240px	30KB
Banner	500-600px	80-120px	1000-1200px	160-240px	50KB
Social icon	20-24px	20-24px	40-48px	40-48px	5KB each

Print this table or bookmark this page. It covers every dimension you will need when building or updating your email signatures.

Frequently Asked Questions

What is the standard email signature size in pixels?

The standard email signature size is 600 pixels wide by 150 to 200 pixels tall. This width matches the default content area in Gmail, Outlook, and most other email clients. Keeping the height under 200 pixels ensures your signature does not dominate the message or get collapsed by clients that truncate long emails. These dimensions work on both desktop and mobile when combined with properly sized individual elements.

What size should my email signature logo be?

Your email signature logo should display at 150 to 300 pixels wide and 30 to 80 pixels tall. Export the source file at 2x these dimensions (300 to 600 pixels wide) so it appears sharp on Retina and high-DPI screens. Keep the file size under 50KB. Horizontal logos work best in signature layouts because they align naturally with the horizontal flow of contact information beside or below them.

How do I make my email signature look good on mobile?

Design your signature at a maximum width of 600 pixels, and test it on your phone before deploying. Make sure your logo is at least 150 pixels wide so it remains legible after scaling. Use social icons that are at least 20 pixels with adequate spacing for tap targets. Avoid stacking too many elements vertically because mobile scaling compresses everything. Send a test email to yourself and open it on both iOS and Android to check readability.

Should I use PNG or JPG for email signature images?

Use PNG for logos, icons, and any image that needs transparency (like a circular headshot crop). Use JPG for photographic content like headshots and banners with photographic backgrounds, exported at 80% quality. Avoid SVG because Gmail and Outlook do not render it. The choice comes down to transparency needs and content type. Compress everything with tools like TinyPNG before embedding.

Why do my email signature images look blurry?

Blurry images in email signatures are almost always caused by using source files at 1x resolution on high-DPI (Retina) screens. Modern screens display at 2x or 3x pixel density, so a 200px wide image needs a 400px source file to look sharp. Export all images at 2x your intended display size, then set the display dimensions with HTML width and height attributes. This ensures crisp rendering across all screen types.

Key Takeaways

Set your overall signature width to 600 pixels maximum and height to 200 pixels maximum. These dimensions ensure compatibility across Gmail, Outlook, Apple Mail, Yahoo, and mobile devices without horizontal scrolling or clipping.
Export all images at 2x your intended display size for Retina sharpness. A logo displayed at 200x50px should be exported at 400x100px. Set the display size using HTML width and height attributes to prevent layout shifts.
Keep total image file size under 100KB across all signature elements. Large images trigger spam filters, slow email loading, and consume mobile data. Compress with TinyPNG or ImageOptim before embedding.
Use PNG for logos and icons, JPG for photos, and avoid SVG in email signatures. Gmail and Outlook do not support SVG rendering. PNG handles transparency for circular crops and sharp graphics. JPG compresses photographic content efficiently.
Always test on the five major clients (Gmail, Outlook, Apple Mail, Yahoo, and mobile) before deploying. Design for the most restrictive client first, then verify everywhere else. Send test emails to real accounts and check every element on both desktop and phone.

Build Pixel-Perfect Signatures with Signkit

Getting dimensions right is half the battle. Keeping them consistent across your entire team is the other half. When one person updates their headshot at 300px and another uses 80px, brand consistency breaks down fast.

Signkit gives you centralized control over every dimension in your team's email signatures. Set your logo size, headshot dimensions, banner specs, and icon sizes once, and they apply to every signature automatically. No more chasing down employees to fix oversized images or blurry logos.

Browse our signature templates to see professionally sized layouts that work across every email client. Or compare Signkit to other signature management tools to see how centralized dimension control saves your team hours of manual formatting.

Your signatures deserve to look sharp in every inbox. Start with the right dimensions, and the rest follows.