Mobile inboxes are ruthless. Most subscribers don’t read emails so much as scan them, making snap decisions in just a few seconds. With mobile devices accounting for the majority of opens, creating mobile-friendly emails that load fast, communicate value instantly, and are easy to read is no longer optional—it’s essential if you want your message to be seen, understood, and acted on.
Optimize for a 3-second read
If you get only one thing from this article, get this: Nearly half of your mobile readers spend three seconds or less with your emails. And that’s counting only the people who read it at all. It doesn’t count the subscribers who cull your email without ever opening it.
This stat applies to desktop readers, too, but on mobile devices it’s even more accentuated. And remember that iPhones make up the lion’s share of mobile email opens.
When you start seeing your emails through the hyper-speed experience lens of mobile subscribers, a lot of the best practices of mobile email fall in line. Of course, some readers will stay with your emails longer, but it’s those first three seconds of assessment that flips the switch of whether subscribers decide to linger … or to leave.
Keep subject lines short
If we’re going to talk speed reading and snap-second assessments, we’ve got to talk about the subject line. And while the sender name is actually more prominent in mobile devices, great email subject lines still count.
Most sources recommend a subject line of about 30 characters for mobile email subject lines. There are also plenty of studies that show longer subject lines work fine.
You can get away with a longer subject line – if you’re smart about how you write the copy. Put the most important information first, then tack details on at the end. That way if someone’s holding their device vertically (aka in “portrait mode”), they’ll get the basics of your message. If they’re got their device turned sideways, they’ll see more of it.
Use pre-header text
When you view your inbox from a mobile device, there’s more room allocated to preheader text than to subject lines. As you know so well, the inbox is super-valuable real estate. So make the most of it and optimize your preheader text. Don’t waste this precious space on the “can’t read this email?” link.
Pre-header text, like subject lines, needs to put the most important information first. Consider starting with copy that is basically a sub-header, or copy that’s a call to action. Or, ideally, copy that is both.
Keep email messages short
Speed matters everywhere. In the context of mobile email, it applies because of the 3-second rule. But speed is also important because of screen size, download times, and conversion rates.
This is not to say that you can’t ever have another email that’s more than one mobile screen. But consider breaking your emails up so each element of them fits in one screen. You’ll focus your readers’ attention, which makes them more likely to follow your call to action.
Think horizontal and vertical
Most of the time, we can be sure our subscribers aren’t reading their desktops and laptops sideways. Not so with mobile devices. And while this is probably just item #143 in the list of things that make mobile designers mad, it is possible to get it right.
Use a legible typeface (and size!)
This is probably the biggest general fail I see in mobile emails. Tiny type just punishes people for trying to read it. So follow Apple’s design cue and use at least 16-point type for body copy and 22-point type for headlines.
Many mobile-friendly email designs are set to expand and contract based on the device they’re viewed on. That can result in very long text lines… which are hard to read unto themselves. Larger type shortens line length to the roughly 50-75 characters recommended by usability experts. And the net-net of that? Your copy gets read, your ideas are understood, and maybe your subscriber clicks.
Limit navigation options
Want the essence of good mobile emails in one word? Simplicity. Because of that, navigation often has to go. Even if it stays, it needs to get trimmed down.
Your emails should always have a clickable logo, of course. And maybe a call to action on the right side of the header. But anything after that is gravy… or possibly even a distraction.
Keep images small
Now, why would I tell you to keep images small, and then show an email with a HUGE header image? To make a point about file size. As mentioned just above, emails must load fast. Like instantaneously. And images are the #1 inhibitor of fast load times.
This doesn’t have to be. Use any one of the free online image compression tools like JPEGmini can keep your files trim. What does “trim” mean? I suggest you try to keep your images below 100kb per image. Of course, if you’ve got just one image in the email, you could probably get away with something larger. But if you’ve got 20 images in the email, it would probably be better to keep each one below 50 kb.
While we’re here, want a hack for boosting click-through rates? Make the images clickable. It blows me away how many smart companies don’t do this. One of the biggest hurdles with tiny screens is to make things easier to click. Fortunately, we’ve got these pretty images that our eyes are just naturally drawn to. Many of us want to click them…
Make your call to actions clickable
This is another variation on the “make things in your emails easy to click” rule, but it’s so critical I couldn’t pass it up. Make your call to actions easy to click. The minimum recommended “clickable” size is 44 x 44 pixels with 10 pixels of space around them, but that really is the minimum. Why make it hard for people?
Also remember that many folks still have their images turned off. So your call to action better work and look nice for them, too. Usually this means a CSS-created button.
Make your social media icons clickable
After tiny type size, this is the next most universal fail of mobile emails. If you’re going to include social media icons, please make them clickable. Let them even take up a whole width of the email. Really.