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If you’re producing image-rich emails and wondering what’s the best email banner size to use, this article explains everything you need to know.

If you get it wrong and use an image that’s too large or small, it can impact the rest of your email and give the recipient an unfavourable impression.

We’ll tell you the best email banner size to use, whether you’re sending for desktop or mobile. 

If you quickly want the ideal sizes without the reasons why; here are the numbers you need to know:

  • Email banner size width for desktop: 600-700px wide.

  • Email banner size width for mobile: 320-385px wide.

  • Email banner size height: maximum of 1728px (ideally shorter)

  • The maximum email file size before message clipping: 102Kb.

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Why is The Importance of Email Banner Size Important?

An email banner is a type of image used in an email. Typically, marketing and other promotional emails use banners to add a splash of colour to the drab look of all-text emails.

You can use email banners in various ways, such as displaying logos, communicating a value proposition, or sharing routine details like contact numbers and addresses.

Here’s what an email banner looks like:

Email banner size sketch


If you’re adding banner images to your emails, you’re likely creating templates in a marketing automation solution 

It’s crucial to get your banner size correct because you will be sending the email to thousands of recipients potentially, and you want your emails to look professional.

Measure your images in pixels.

Commonly, most measure images in pixels—abbreviated as ‘px’. A pixel is a tiny dot of shade or colour (which you can see on a screen when you get up close to the display).

An image or email banner is typically stated with the width of the image followed by the height. i.e. 600 x 450px.

Problems encountered when using the wrong email banner size.

If you use an email banner size unsuitable for your layout, it can affect the structure of any associated text and jumble your email’s appearance.

Most have experienced layout-shift in a word processing document when you move an image slightly, and it ruins the rest of the document.

A further problem caused when you use an email banner that’s too wide is that the recipient’s email client inserts a horizontal scroll bar to your message.  

Email recipients don’t need much excuse to abandon engagement with an email.

So you increase the chance that your email will have less impact if you make your email hard for recipients to read.

How wide should an email banner be?

You may come across outdated information online that recommends email banners should be no wider than 600px.

Originally, this advice was given when screen resolutions topped out at 1024×768. (Meaning the largest image a screen could display without scrolling was 1024 pixels wide and 768 pixels high.)

The most common email client at the time was Microsoft Outlook. It needed some of that width for menus and folders, so the space it provided for email content was 600 pixels wide. It was effectively imposing a limit on email banner widths to 600px (without horizontal scrolling).

Today, computer displays have higher resolutions. The most common screen resolution is 1920 x 1080. Additionally, browser-based email clients provide email banners with a little more on-screen real estate to use.

Today, the width of your email banner should be between 600-700px wide. Here’s an email from Door Dash that’s 700px wide.

Email banner size door dash


Email Banner Width on Mobile

Email recipients view messages on both desktop and mobile. It’s not unusual for your email to be first opened in one format, then later in another. According to Litmus, 43% of emails are opened for the first time in a mobile client.

As a result, you need to create an email banner image for both desktop and mobile.

Most marketing automation tools provide the facility to build your email templates with a mobile and a desktop view. Your software may automatically create a mobile responsive version of your desktop email, or you may need to upload two sizes of your email banner image.

The best email banner size to use on mobile is between 320-385px wide.

If you use a 640px image width for desktop and create two columns in your image, it converts more readily into a single column banner for mobile that’s 320px wide.

How tall should an email banner be?

The height of your email banner image will depend on whether you’re creating a full-image email or using several smaller banners spaced out with text.

You can use as many banner images as needed throughout your email. One for the header image, several in the body, and banner images are common in an email footer to display routine business information.

Email banner size inspire

Everyone is familiar with vertical scrolling online, so you’re not so constrained on banner length up to a point. However, you should think about what your recipient sees as soon as they open your email.

An old newspaper term describes the part of an email that is immediately visible without scrolling – ‘above the fold’.

This section of your email is between 300-500px, and it’s best if you use it to communicate your value proposition to a recipient immediately. That way, at the very least, your reader understands what your email is about and may continue reading it. 

If you’re thinking of using tall email banner sizes, make sure that your headline displays above the fold.

Maximum email banner size height.

If you’re using an email banner image as your entire email content, the more text you use, the longer your email banner will be.

Microsoft Outlook, the email client of choice for many businesses, caps the maximum image height at 1728px. If your image is taller than this, Outlook will trim and compress your image, obscuring parts of the content.

Keeping your images under this length is good email marketing practice anyway. Boomerang performed an in-depth study of email text length in 2016. They tracked 40 million emails to discover the ideal amount of text, concluding that the sweet spot for email length was 50-125 words. 

Tall email banner sizes tempt you to use too much text, and you can fall foul of another aspect that relates to email banner size; overall email file size.

What is the maximum file size for email banners?

The maximum size of your email banner is, in part, dictated by the message size limits of popular email providers.

Both Gmail and Yahoo clip messages once they exceed a specific size. It’s not about the length of an email; a text email can go on and on. It’s about the amount of storage space an email takes up once the text and images are added together.

Both Gmail and Yahoo clip an email message if it exceeds 102Kb in size. When your recipient scrolls down your email and reaches the 102Kb limit, they see a notification like the one shown below.

Tall email banner sizes tempt you to use too much text, and you can fall foul of another aspect that relates to email banner size; overall email file size.

Email banner size

The two primary drawbacks to having your message clipped are:

  • Your recipient doesn’t read your entire message unless they take another action.

  • The code that tracks the recipient’s behaviour with your email is usually located in the email footer. The clipping stops its activation, so you lose valuable engagement data. 

You can reduce your overall email file size by compressing any images before uploading them to your template.

You can find an image compressor with a quick Google search; is popular and free if you do one image at a time.

What’s the best size for an email signature banner?

Even if you don’t regularly create image-rich emails, you may want to use an email signature banner in your plain text ones. Email signatures save time otherwise spent adding the same information like your job title and contact details to every email you send.

Email signature banners brand your businesses emails, ensuring a uniform, professional look.

Email signature banners follow many of the same rules as other types of email banner sizes.

If you are using a white background in your email signature banner, you can size the image to fit your content. This should keep the file size small, saving Kbs of space for the rest of your email.

If you want to use colour to add contrast to your email, size your email signature banner between 600-700px to fill the width of an email.

There are fewer restrictions on your email signature banner’s height; a typical height used is between 150-200px. As long as you keep it under the 1728px maximum and consider the overall message size of 102Kb, you can use the size that works best for you.

Key Takeaways

Email banner sizes are not as constrained as they once were when desktop and mobile displays had poorer screen resolutions.

For an email banner width, the ideal size is 600-700px on desktop, and 320-385px on mobile.

For email banner height, you should keep the image under 1728px, but be aware that the section of your email that displays without scrolling ‘above the fold’ is approx 300-500px.

Keep your overall email file size under 102Kb, and compress images before adding them to your email template.  

Harness the Power of Email Marketing

When it comes to the best email marketing software in Australia, your business needs to weigh up your needs and balance them against your country’s data security laws.

It’s one thing to commit to a piece of software that has all the functionality and features you desire, but it’s another thing completely to find software that stores your data legally and securely.

Is your business currently using email as part of your marketing strategy? Do you need help with the creation and automation of your emails, or would like to increase engagement of them?

Here at Swift Digital, we can help you with your email marketing by providing tips on email marketing best practices to make your email campaign a success!

The Preferred Email, Events and SMS Automation Software For All Australian Government Departments

Swift Digital’s templates help you effortlessly create stunning emails and events communications using our drag-and-drop email and event builder.

You can raise engagement with embedded images, videos, polls, article feedback, and emojis and schedule messages to send at the right time.

Government departments’ unique marketing requirements are covered with Swift Digital, and full compliance with all anti-spam and privacy laws is guaranteed. Swift Digital is also ISO 27001 certified.

Swift Digital is Australia’s leader in marketing automation software and event management working with organisations like the NSW Government, ATO, and companies like Westpac Bank and Qantas.

Find out why we’re the Australian government department’s number one choice for their professional communications and events.

To find out how your business can get the best out of Swift Digital’s platform, contact our team today.

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