We’ve all read and understand the significant volume and value that email marketing has to commerce, whether it’s B2B or B2C. If you’re a CMO or CEO, you may just want to know that more of-the-moment communication methods may not be as valuable as one of the oldest— email marketing, with an ROI of $36 for every $1 spent. And that ROI generates itself, in part, in the sheer volume of email marketing.

As of April 2023, the U.S. sends the most emails per day at 9.8 billion, followed by the U.K., Japan, India, Belgium and the Netherlands at 8.3 billion, reports Statista.
“Over 80 percent of industry experts stated that they used e-mail newsletters as part of their marketing strategies in 2022, while also employing various metrics to evaluate a campaign’s success,” Statista reported. “In 2022, the highest click-to-open rate (CTOR) of marketing e-mails globally was tracked in the financial service sector, followed by the publishing one. The e-mail unsubscribe rates from various countries that year remained under one percent. More than 60 percent of marketers indicated that their e-mail campaign open rates improved in 2022, indicating the stable progress of this digital channel.”

So, that’s why we continue to send (and receive!) emails. But even though email marketing is an old friend, the way people read and interact with email continues to evolve, which leads to why your email marketing must be mobile:
#1 – Over 70% of all emails are opened on mobile devices.
This statistic just supports why mobile is important for email, as it’s not breaking news that people use their mobile devices everywhere they can get service, but specifically at home and work and in stores, restaurants and bars, according to Google.
And those out-and-about statistics aren’t just for social media checks or QR code reading. They include email. Google found that 71% of smartphone users check their email using email apps (most-often in the late morning).
#2 – Mobile Display is Everything
Of that approximately 70% of mobile users opening emails on a mobile device, 72% of them will delete the emails, particularly if it doesn’t display correctly on their device.
This tidbit of must-know shows that marketers have to make sure their emails are not only mobile-friendly, but also responsive and know that mobile-friendly email is not necessarily responsive, but a responsive email is almost always mobile-friendly. Mobile email templates are easier to design, but they come with fewer customizable options. Responsive emails require more time and coding to develop, compared to mobile-friendly ones, but not all smartphones support responsive design. What? Why does that sound convoluted?

Let’s clarify: Mobile-friendly emails can be a fixed-width, such as 320px—width of the screen in portrait mode—and remain mobile-optimized. Font sizes don’t change, depending on screen size, but remain large enough to be read on smaller screens. Mobile-friendly emails can hold a multi-column layout and allow readers to tap and zoom into individuals blocks of content. Mobile-friendly requires large, thumb-tappable buttons (remember we all have fat fingers on mobile!) for CTAs. Avoid web links, please, unless there’s only one. Too many are like a big party—you can’t get to every guest easily.
Responsive emails use media queries to adjust email width, dependent on the size of the display. Responsive emails adapt to larger screens, such as found on the Samsung Galaxy Z Fold 4, Samsung Galaxy S22 Ultra 3, Apple iPhone 14 Pro Max and Google Pixel 7 Pro. The width adapts to any display size in any orientation.

Font sizes in responsive emails change from desktop to mobile displays and several different display sizes can be targeted when you use different media queries. Two of the best features of responsive emails are that layout can be changed from multi-column to single-column immediately and different elements (think image buttons) can be hidden and shown contingent on the platform where the email is viewed. Using a responsive email template will make emails look inviting on any device by fitting them to the screen.
When designing mobile email, Mailchimp writes in its mobile email guide that the company follows the mantra one eyeball, one thumb, and arm’s-length.
According to Mailchimp, the translation of this refrain is “on a small screen, an email should be easily readable with one eye, any links and calls-to-action usable with one thumb, and any text or visual cues large enough so that all of the above can be done comfortably at arm’s length.”
Getting to this one eye, one thumb and one arm objective means designing with a minimum font size of 16px. Apple recommends 17-22px and Google recommends 18-22px. CTA touch targets, such as buttons, should be at least 46px squared. Apple recommends 44px squared and Google recommends 48px squared. Avoid clustering several links in copy, which makes them difficult to access. Find other guidance here.

If you want to go into the weeds on responsive design, consider Mozilla’s tutorial, and for more on mobile engagement, see Mailchimp’s impact on engagement with mobile.
Also, as an aside, double opt in (DOI) no longer rules ROI, particularly on mobile. Single opt in (SOI) programs show an 80% higher return than DOI programs in general, but the hassle associated with a DOI on mobile is often a dealbreaker for mobile email users. Unless regulatory compliance compels the market, the DOI best practice may evaporate.
#3 – Mobile email fits hand-in-glove with personalization
If you want to boost mobile email open rates, click-through rates, and response rates, send more personalized emails. It could be that simple, according to Shopify’s perspective on personalization in eCommerce.
With an automated email marketing service, you can segment your email list and automatically send personalized emails, based on demographics, interests, activity on your website, or purchase behavior.

This is particularly effective for abandoned cart emails on eCommerce sites. Shoppers who leave a site without checking out should get an email reminder and if the email is personalized to the users’ actions or preferences, they are more likely to open and interact with the email. See suggestions on how to stand out with personalization.
Oh, one more thing. If you or your business is concerned with accessibility in email, across all devices, consider Harvard’s guidelines on creating accessible emails. It’s important.
If you’d like greater insights or guidance on mobile email marketing, let’s have a conversation. Call or email (see what we did there?) ER Marketing and let’s talk.
FAQs
Email marketing maintains its value with an ROI of $36 for every $1 spent and steady progress. In April 2023, the U.S. sent the most emails per day at 9.8 billion.
Over 70% of emails are opened on mobile devices, reflecting the widespread use of mobile devices for communication, including email.
Around 72% of mobile users will delete emails that don’t display correctly on their devices. Marketers must ensure emails are mobile-friendly and responsive.
Mobile-friendly emails have fixed-width design, while responsive emails use media queries to adjust to various display sizes. Responsive emails adapt layout and hide/show elements based on platform.
Design emails for one-eye readability, one-thumb interaction, and comfortable arm’s length viewing. Maintain a minimum font size of 16px and appropriate touch target sizes for CTAs.
Personalized emails boost open rates, click-through rates, and response rates. Automation allows segmentation based on demographics, interests, website activity, or purchase behavior.
Sending personalized reminders to users who abandoned their carts can be highly effective, increasing the likelihood of them opening and interacting with the email.