When sending emails, you want to make sure they look great in your subscribers’ inboxes. But with countless email clients out there, optimizing for every single one isn’t realistic. Fortunately, by focusing on just a few of the most popular email clients, you can easily optimize for the vast majority of your list.

So which email clients should you prioritize? Email analytics platform Litmus analyzed nearly 10 billion email opens to see which clients people are using. Here’s what they found.

Email clients ranked by popularity

The most popular email clients are Apple iPhone and Gmail. Together, they make up 65% of all clients used to open Litmus emails.

Apple Mail (for desktop) comes in a distant third at 10%. Outlook’s desktop app is in fourth place at 7%.

Graph depicting market share of most popular email clients.
Data source: Litmus 2020 State of Email Engagement Report

Why email clients matter

Now that you know the most popular email clients, you can focus on making sure your emails are optimized for iPhone and Gmail.

What does that mean? Here are some things to consider.

Mobile optimization – Mobile responsive emails have long been a best practice of email marketing. These numbers show why they’re so important. According to Litmus, 39% of all email opens (regardless of client) happen on mobile.

Subject line length – When writing email subject lines, make sure they won’t get cut off on an iPhone screen.

Email preview on iPhone screen that cuts the L off the word pool in a subject line.

HTML capabilities – Different email clients support different HTML capabilities. For example, if you embed a video in an email with HTML, some clients will display it and some won’t. If you’re using an email marketing tool, you don’t need to worry too much about this. They’re designed to code your emails in a way that will look good on most clients.

Testing priorities – It’s always a good idea to send yourself a test email before sending to your entire list. You don’t have to make an account with every email client under the sun, but it’s smart to include a Gmail address and an iPhone user on your test list.

Check the most popular email clients for your list

Litmus’s data comes from billions of email opens. That’s a pretty good dataset, but it’s important to remember that every mailing list is unique. A B2B company may see more Outlook users than a consumer brand does. Some email clients are popular in certain countries, but unheard of in others.

So take a look at your own email analytics dashboard and see which clients people are using to open your emails. Once you know that, you’ll have yet another way to optimize campaigns and create a great email experience for subscribers.

Kate Lindemann

Kate Lindemann | Canto

A marketing and digital communications specialist, Kate helps brands connect with customers – from crafting the perfect message to finding the right way to deliver it.