What Is The Best Email Signature Size?

What are the best dimensions and file formats for email signatures and banners, and why? Here’s our complete guide.

Email signature and banner size matters. Why? Because you want to communicate the key details about you, your brand and your business.

Here is our email banner and signature size guide – including ideal signature dimensions, image file size (weight), resolution and font sizes – to help you easily create and manage the most effective email signatures and banners.

Email Signature on multiple devices

What is the best email signature banner size?

The best email banner size is 650 pixels wide and between 90 and 150 pixels high. This ensures that your email banner will be easily viewable (but not obstructive) in any preview pane or smartphone.

Recommended email signature size

Why is email banner size important?

  • This size focuses you to use a clear, concise headline and simple eye-catching imagery. Don’t overcrowd your banner with too much text.
  • With Rocketseed a banner can be displayed at the top or bottom of your email and the correct dimensions create impact without overwhelming the recipient.
  • We suggest image width are a maximum of 650px because that will fit the entire image onto one page width if the email is printed
  • The correct email banner dimensions ensure that your email banner will be easily viewable in any preview pane or smartphone

What is the best email banner file size and resolution?

  • Email banners should be created as .PNG files and should be designed to a web resolution of 72dpi to display correctly on 100% zoom view.
  • The email banner image file should be no larger than 40kb to ensure the additional ‘weight’ of the email is kept minimal.

What is the best email signature size?

The ideal size for email signatures (both text and image) is no more than 650 pixels wide and between 90 and 150 pixels high. This allows for images (headshot, logo, promotional banner) and contact information to be kept streamlined without dominating the email.

Icon showing a horizontal ruler.


We recommend an email signature width of 650 pixels. Please note, when using both signatures and banners we recommend that the widths are the same.

Icon showing a vertical ruler.


90 -150 pixels high should be sufficient. There is no height limit for email signatures but recipients don’t want to keep scrolling through a long signature, especially in an email chain.

What is the best file size and format to add email banner animation?

Use GIF files to add animation to your email signature banner. For best performance, keep your banner GIF file size below 45kb by limiting the number of frames. We recommend 2-3 frames with 2-3 seconds between them and image resolution to 72dpi.

Simple animation such as changing product images or colour choices draws attention to your message.

Some email clients do not support animation and will display the GIF as a still image. Therefore feature your most important message on the first GIF frame so, even without animation, recipients will get your main message.

We recommend that if you’re planning to use an animated .GIF that this only has one clickable link, and does not use image maps at the same time.

Email banner examples

What are the best logo dimensions for an email signature?

Your company logo is essential for branding your email signature. We recommend the best email signature logo size of 100 pixels wide 100 pixels high. Of course, logos vary in shape so it is impossible to provide an absolute optimum width and height.

It is essential that your logo looks sharp on all devices avoiding pixelation.

What is the best email signature image format?

For email signature images we recommend using .PNG files with transparent backgrounds. These will better preserve the integrity of your design in dark mode. Rocketseed also supports JPEG files for images and GIF files for animation. Both PNG and JPEG formats are easy to compress without losing image quality. Do not use WebP or SVG image file formats in your email signature.

Example of an email signature with images

How many images should be in your email signature?

Try to stick to just one or two high-quality images – company logo and headshot photo – to avoid your email signature looking busy, particularly on mobile. A promotional banner image can also be added under your signature for additional impact and engagement.

  • If you choose to use transparent backgrounds for images, bear in mind that white, dark grey and black text may have rendering issues in either light or dark mode.
  • Emails with images over the size of 15kb show the images as attachments in Google inboxes.

What is the best image dimensions to include in your email signature?

The best image size to include in your email signature is approx. 300-400 pixels wide and 70-100 pixels high. For example, a business award or accreditation logo.

What is the maximum file size for email signature images?

The combined file sizes of images within the email signature should be less than 40kb to ensure the ‘weight’ of the email is controlled.

What is the best image resolution to include in your email signature?

We recommend saving your images to a web resolution of 72dpi to display correctly on 100% zoom view.

What is the best image shape for email signatures?

When adding email signature images, it is best to choose simple designs and shapes such as rectangles, squares and circles. These are impactful and easy to incorporate.

What is the best email signature social media icon size?

We recommend keeping social media icon size in your signature relatively small, say 22px x 22px, so that they do not overpower your logo or key contact details.

Use a larger size to give more emphasis to your social media if required but remember to only feature social profiles that are actively managed with current, regularly updated content.

Social media icons
Mobile email signature example

Email signatures on mobile

When creating an email signature that includes images, remember to adapt it for mobile. 81% of people open emails on mobile, if the signature is pixelated or distorted, it will appear unprofessional.

Scaling images down while keeping the aspect ratio within the design and keeping HTML text legible is Rocketseed’s aim when displaying signatures on mobile devices.

What is the best font size to use in an email signature?

We recommend using a font size of between 8pt (11px) and 20pt (26px) so your email signature is easy to read without distracting from your email’s content.

To ensure all text displays correctly, we recommend using only web safe fonts in your email signature.

What is the best email signature size for replies and forwards?

Using shorter ‘reply’ and ‘forward’ email signatures is the smart, simple way to keep your emails on-brand without crowding email chains. Simply make a copy of your full master signature and delete the components you feel aren’t needed for your shortened signature. Your ‘reply’ signature could be shortened to feature just name, job title and company logo.

Rocketseed links your full and shortened signature templates so the shortened version is automatically applied to all employees’ ‘reply’ and ’forward’ emails.

Embedded vs. referenced images

To look professional and on-brand, it is essential that your email signature and banner images always display correctly. Images can be either embedded or referenced, with the following differences.

Embedded images are displayed automatically as soon as the email is opened.

Referenced images are hosted externally with your email linking to them and not immediately visible, requiring to be downloaded each time the message is viewed. By default, most email programs, such as Outlook or Gmail do not display referenced images.

Email signature size information for Gmail

Gmail logo.

Gmail signature size

170 pixels high and 200 pixels wide are the ideal email signature dimensions for Gmail. In terms of text content, Gmail has an email signature limit of 10,000 characters.

Gmail signature images

For Gmail users, the best image size is around 80 pixels high and up to 200 pixels wide. PNG is the best format for Gmail signature images.

Email signature size information for Outlook

Outlook logo.

Outlook email signature size

In Outlook, the best email signature size is 170 pixels high and 200 pixels wide. In terms of text content Outlook has an email signature limit of 5,000 characters.

Outlook signature image size 

For Outlook email signatures, the image size is recommended to remain within 650 pixels wide. If you don’t want to have to resize an image in email signature Outlook, then make sure your image is no larger than 10KB.

Outlook signature logo size 

A logo size of 100 pixels wide and up to 100 pixels high is suitable for Outlook email signature. As with all images, if re-sizing is required, be sure to lock the aspect ratio to keep your logo proportions correct.

Control consistent email signature sizing company-wide

It is important that the best email signature size is used consistently by all employees across your business. To ensure that employees cannot customise email signature size, say by adding quotes or additional social channels, it pays to use an email signature solution that gives you centralised control. That way, all email signature sizing will be consistent company-wide.

Some key things to avoid

  • Don’t let individual employees customise their own email signature size.
  • Don’t features all email signature information as an image, as this can end up in spam folders.
  • Don’t use too many fonts and keep all text easy to read.
  • Don’t miss out any important information simply because of size.
  • Don’t overcrowd your design.
  • Don’t use too many images – limit to headshot, logo and banner.
  • Don’t include social media icons for profiles that are not actively managed.
  • Don’t include any images that are not in keeping with your company brand.

Simplify signature sizing with email signature management software

When you use email signature and design management software like Rocketseed, email signature sizing and images become simple and stress-free.

Whether you customise a Rocketseed email signature template or instruct our professional team to design you a bespoke email signature, you are guaranteed it will be optimally sized for the best results.

Rocketseed also embeds all images by default so your email signature will always display correctly across all email clients and devices.

Rocketseed’s also gives you centralized control of ‘tamper-proof’ employee signatures so you can be sure that all employee email signatures will be consistently sized and branded company-wide.

Download our latest Email Signature Design Guidelines:

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