Best Email Signature Size & Dimensions Guide

‍

The Cheat Sheet

If you only need the quick answer, use these e-mail signature dimensions:

• Max width on desktop: 600 px
• Max width on mobile: 320 px target, or a fluid layout that scales down cleanly
• Ideal total height: 150 to 200 px
• Logo display size: 120 to 200 px wide
• Headshot display size: 100 x 100 px or 150 x 150 px
• Banner size: 600 x 100 to 150 px
• Individual image file size: ideally under 50 KB
• HTML weight: keep under 100 KB, ideally under 80 KB
• Export setting: 72 PPI is a common web export setting
• Retina rule: upload images at 2x the display size, then display them smaller

‍

These numbers align with current email design guidance from Exclaimer, Mailchimp, Litmus, and the benchmark articles from WiseStamp and Newoldstamp. Exclaimer recommends 600 px width for desktop and 320 px for mobile, with 150 to 200 px as the ideal height. Mailchimp still recommends staying within a 600 to 800 px email width because preview panes are narrow, while Litmus notes Gmail clips messages when HTML exceeds 102 KB.

‍

What Is the Best Email Signature Size?

‍

The safest email signature size for most companies is 600 px wide and 150 to 200 px high.

Why 600 px? Because email clients are still far less forgiving than websites. Mailchimp’s email design reference recommends widths between 600 and 800 px for HTML emails, and specifically warns that narrow viewing panes can cut off messages wider than that range. Exclaimer goes further and recommends 600 px as the ideal desktop signature width. In other words, 600 px is the practical sweet spot: wide enough to fit your name, role, contact details, logo, and a small call to action, but narrow enough to behave well in Gmail, Outlook, and preview panes.

Height matters too, but less than width. A signature that becomes a tall block under every email quickly feels intrusive. Keep your email footer size around 150 to 200 px high so the signature supports the message instead of overpowering it. That range also matches current benchmark guidance from Exclaimer and WiseStamp.

If you go much wider than 600 px, two things usually happen. On desktop, the signature can start feeling bloated inside preview panes. On mobile, it may wrap awkwardly, squash, or scale down until the text becomes tiny. Exclaimer’s support documentation specifically notes that overly wide templates can break on smaller screens, and fixed-width layouts can cause mobile scaling issues.

‍

Email Signature Image Size: Logos and Headshots

‍

When people search for email signature image size, they usually mean one of two things: the logo or the headshot.

For a logo, keep the displayed size around 120 to 200 px wide. For most horizontal logos, 300 x 100 px should be treated as a hard ceiling, not a target. Exclaimer’s guidance includes a 200 x 100 px example, while Newoldstamp suggests around 100 x 100 px as a general benchmark for logos in compact signatures. The exact number depends on your brand mark, but the core rule is simple: your logo should support the signature, not dominate it.

For a headshot, use 100 x 100 px if you want a compact layout, or 150 x 150 px if the photo is a more important part of the design. Anything much larger usually wastes horizontal space that is better spent on readable contact details.

Here is the important part most people miss: the displayed size and the uploaded size are not the same thing.

High density screens use more physical pixels to display the same CSS size. MDN explains this through devicePixelRatio, and Litmus shows the practical email version of it: if you want an image to display at 100 x 100 px, upload it at roughly 200 x 200 px and scale it down in the HTML. That is the easiest way to keep logos and headshots sharp on Retina and other high DPI screens.

For example:

‍

• Displayed headshot: 100 x 100 px
• Uploaded source image: 200 x 200 px
• Displayed logo: 150 x 50 px
• Uploaded source image: 300 x 100 px

‍

That said, email clients can be awkward. Exclaimer documents a common problem where some clients revert an image to its original size when replying or forwarding if the uploaded file is larger than the displayed size. Litmus also notes that Outlook may need explicit width and max-width handling for retina images. This is exactly why manual image scaling in email HTML is so frustrating.

‍

File Size Matters: Why KB Count Matters

‍

The best email signature dimensions in the world will not help if the signature is too heavy.

Litmus separates email weight into two parts: HTML weight and loaded weight. HTML weight is the size of the code itself. Loaded weight includes everything needed to fully render the email, including images and fonts. Gmail clips messages when the HTML exceeds 102 KB, and Litmus recommends staying under 80 KB where possible.

That is why the smartest rule is this:

‍

• Keep the signature HTML under 100 KB
• Keep individual images under 50 KB whenever possible
• Avoid unnecessary icons, giant photos, and heavy GIFs

‍

Exclaimer recommends keeping signature images below 50 KB, while WiseStamp suggests limiting signature images and treating 100 KB as the upper boundary.

Also, do not confuse HTML clipping with image weight. Litmus points out that Gmail’s 102 KB clipping threshold applies to the HTML code, not the image bytes themselves. But large or uncompressed images still increase loaded weight, slow rendering, and create a worse user experience, especially on mobile connections.

As for file format:

‍

• PNG is usually best for logos, icons, and graphics that need transparency or sharp edges.
• JPG or JPEG is best for headshots and photographic images.
• GIF can work for simple animation, but it gets heavy fast, so use it carefully.

‍

If your image contains text, sharp lines, or transparency, PNG is usually safer. If it is a real photo, JPEG will usually give you the best quality-to-file-size balance.

‍

Mobile Optimization: The 320 px Rule

‍

If you ignore mobile, you are designing your signature for the wrong screen.

Exclaimer recommends 320 px as the ideal mobile email signature width because mobile screens commonly fall between 320 and 500 px wide. Newoldstamp makes the same point: around 320 px is preferable if you want the signature to fit portrait mobile screens cleanly.

This matters even more because Apple and Gmail dominate modern email opens. Litmus’ January 2026 market share report shows Apple at 46.56% and Gmail at 25.45%, and Litmus notes that almost 90% of opens report as Apple or Gmail. That is a strong reminder that your signature must work across phone-driven ecosystems, not just on a wide desktop monitor.

So what should you actually do?

First, avoid a rigid, complex, multi-column layout if mobile readability matters. If a fixed-width 600 px signature is simply shrunk to fit a phone, the result can look tiny. Exclaimer even notes that some iOS devices use fit-to-screen behavior, which can make wide fixed templates appear very small.

Second, stack important elements vertically when needed. A mobile-friendly signature often works better like this:

‍

Name
Job title
Phone
Email
Company
Logo or headshot
Banner

‍

That is not as visually fancy as a wide desktop layout, but it is far more readable on a phone.

Third, keep the links easy to tap and the text large enough to read at arm’s length. Mailchimp specifically recommends designing with mobile friendliness in mind and making links thumb-friendly.

‍

Email Banner Size

‍

A banner can be useful, but only if it stays secondary to the message.

When people ask about email banner size, email signature banner size, or email banner dimensions, the most practical answer is this: use a banner that matches the signature width and stays relatively shallow.

A safe recommendation is 600 px wide and 100 to 150 px high.

That number is not random. Exclaimer says banners with a maximum width of 650 px and a maximum height of 100 px perform well, and also recommends banner sizes in the 300 to 400 px by 70 to 100 px range for compact implementations. Newoldstamp suggests a maximum of 700 px by 100 px, while WiseStamp recommends roughly 500 px by 120 px. Put together, the consensus is clear: keep banners wide enough to align with the signature, but short enough that they do not become the star of the email.

If your signature is 600 px wide, then your email signature banner size should usually be:

‍

• 600 x 100 px for a minimal banner
• 600 x 120 px for a balanced banner
• 600 x 150 px as the upper comfortable limit

‍

Anything taller starts to feel more like an ad than a signature.

‍

The Easy Fix

‍

The best email signature size is not about making everything bigger. It is about making everything fit.

Use 600 px as your desktop maximum width. Design for 320 px mobile screens. Keep the total height around 150 to 200 px. Use smaller, optimized images. Keep your HTML under 100 KB and your image files as light as possible. If you use high DPI assets, upload them at 2x the displayed size so they stay crisp on modern screens.

You can absolutely spend hours resizing logos, testing Outlook quirks, compressing banners, and tweaking HTML width attributes by hand.

Or you can use gSignature.

‍

Manual scaling in email HTML is a headache, especially when different clients handle image sizing, retina rendering, replies, and forwards differently. With gSignature, you upload your assets, and the generator helps optimize the email signature image size, email signature logo size, email banner size, and overall email footer size automatically.

Create a perfectly sized email signature in 2 minutes. Let the editor handle the pixels for you.

‍