With the plethora of email clients out there, marketers have to account for a lot of variables when creating their emails. And we’ve spent years chronicling our issues with coding and designing emails in Microsoft and Gmail. On more than one occasion, we’ve successfully anticipated changes to how these email clients read and support email designs.

But most email marketers today aren’t coding their own emails from scratch.

Thankfully, modern email design tools like Campaign Monitor take much of the guesswork out of crafting a beautiful and function email and you can know how your email will render before you ever push send.

Even so, it’s still important to know where your subscribers are reading their emails in order to maximize how many of your emails are landing in the right inboxes and how they look and perform when they get there.

So what are the most popular email clients out there and how do we know which ones your subscribers are using?

The top ten email clients (calculated from 946 million opens) are as follows:

Source: Email Client Market Share

Fine print: This leaderboard of the most popular webmail, desktop, and mobile email clients is compiled from data collected worldwide by Litmus Email Analytics, and displays up-to-date figures for the top 10 email clients as of November 2018.

Since determining the client in which an email is opened requires images to be displayed, the data for some email clients and mobile devices might be over- or under-represented due to automatic image blocking.

As you can see from this data, Apple Mail and Gmail lead other email clients by a longshot. In fact, Gmail just announced they have surpassed 1.5 billion users on their platform.

This means that you should keep Apple Mail and Gmail in mind when you’re designing your emails in order to provide a seamless experience for your subscribers and simplify the design process for your marketing team, especially if that team is just one person.

Which email clients are your subscribers using?

Each time a subscriber opens an email sent with Campaign Monitor, we keep track of which email client they’re using. You can see this in the Reporting section of your account under Email Client Usage.

Here’s an example:

In the example above, understanding that the majority of subscribers are viewing the email in Gmail and on iPhones will help you optimize your email design for the most opens and click-through rates on mobile devices.

For instance, knowing your specific users’ email clients will help you choose the best length for your email subject lines: You’ll want your subject line to be between 41 characters (the optimal number for portrait view on an iPhone) to 70 characters for Gmail.

Familiarizing yourself with today’s top email clients allows you to learn the limits of each and design your next email with these limitations in mind; this means no more worrying about images not displaying, subject lines getting cut off, or spam filter surprises.

Instead, you can feel in control of your email marketing campaigns.