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How to Optimize Email for Mobile – Part II: 8 More Best Practices

by | Dec 17, 2014 | Online Mktg. and Copywriting, Lead Generation, Email Marketing, Email newsletters and e-zines, Content Marketing | 0 comments

The rise of online mobile devices is changing the way people communicate and gather information. One big change is in the way we consume email.

As we saw in Part I of this series, nearly half of all commercial email is now opened for the first time on a mobile device.{1} We also learned that 87% of mobile users surveyed said they would delete or unsubscribe if an email did not display properly on their smartphone or tablet.{2}

In other words, for B2B marketers, it’s now essential that we optimize our emails for mobile consumption.

Last month, I presented seven best practices for optimizing email for mobile (If you missed that article, you can read it here). Today, I offer you eight more.

Here they are:

1. Keep file sizes small

As I mentioned last time, mobile users tend to be busy and in a hurry. They want your email to open without delay.

So you need to be aware of email file size.

Page loading speed is directly proportional to file size. And while mobile Internet speeds are increasing, they still lag desktops by an average of one second per page load, according to Google (see graph, below).{3}

That’s important, because a recent Aberdeen study found a one-second delay in loading translated into a 7% reduction in conversions.{4}

Thus, you’ll want to keep your email files as small as possible.

Page Load Time: Desktop vs. Mobile, 2012 vs. 2013

Source: Google {3}

Two keys to minimizing HTML email footprint are (1) efficient HTML code and (2) small image files.

Formatting and editing in your service provider’s HTML editor can cause tons of redundant code to be stored in your email file. Thus, the first step in optimizing file size is to have someone with HTML familiarity go through your email and strip out that unnecessary code.

Image files can have an even greater impact on email size. Luckily, large images can be compressed without diminishing online viewing quality using any good photo editing application. Content with images attracts more page views, so making images render quickly is preferable to eliminating them.

2. Size images with mobile in mind

Make sure the images you imbed in your emails don’t extend off mobile screens. No one wants to scroll sideways and see only a portion of an image at a time.

The best way to deal with image files is to resize them automatically as a proportion of screen width. My responsive template does that for me, resizing to screen width every image that’s wider. If yours doesn’t, simply alter the image style attributes in your HTML editor, as in the following example, where XX indicates your desired proportion:

3. Plan for an images-off environment

Don’t assume that the images you imbed in your email content will be displayed on every mobile device. Some mobile email apps turn off images by default, and many mobile users opt to turn them off themselves.

Plan for this scenario. Be sure your message is conveyed clearly when images are turned off. If an image you’re using provides significant information, be sure the same information is described in your email’s text, as well.

4. Use short, front-loaded subject lines

This is a good tip for email in general, but even more so when mobile is taken into consideration. With some mobile platforms, you may get as few as 27 characters of your subject line displayed, compared to 40 for most desktop clients.

So keep your subject lines as short as possible. Try to get the main point across in the first four or five words, and test different subject lines to optimize response.

5. Make the most of pre-header space

The pre-header is the text displayed at the very top of your email. It is often used for messages like “To view this email as a web page, click here.

What many don’t realize, however, is that in a mobile inbox, the pre-header is also displayed just below the subject line. This gives you extra real estate to work with when trying to convince prospects to open your email. Use that space to convey important information that wouldn’t fit in the subject line itself.

6. Make it easy to click

Nearly all commercial emails include clickable links aimed at getting prospects to take a desired action. But mobile users don’t have a precision-guided mouse cursor to help them select the links they want. They have to make due with big fingers on a relatively small touch screen. Your emails need to take this factor into account.

It’s a good idea to make call-to-action buttons relatively large. Apple’s iOS Human Interface Guidelines recommend minimum dimensions of 44 x 44 px. {5}

You should also be sure to leave sufficient vertical space between links and buttons. Avoid placing them in successive lines, and break up paragraphs to create additional spacing, if necessary, to avoid “mistaps.”

Also, use classic underlining to make hyperlinks easy to recognize. On a small screen – and with no cursor rolloveer to cue alternate text – colored text in a paragraph may appear too be simply highlighted, rather than clickable.

7. Consider adding click-to-call

Smartphone users will find it much easier to place a phone call than fill out a form. You can make it even easier. Let them convert with just one click by providing your phone number in click-to-call format.

Click-to-call on mobile device screen

Source: Campaign Monitor

Click-to-call links can be installed easily as either plain text or buttons. See this article from Campaign Monitor for details on how to style them in your HTML emails.{6}

8. Provide a plaintext version

This is general best practice for email marketing, both for CAN-SPAM compliance and because many spam filters will reject messages which don’t offer both an HTML and a plaintext version.

It is especially relevant to mobile, however, as some mobile email clients do not support HTML, and many mobile users are selecting to receive text-only email.

Most email marketing services provide facilities that automatically generate a plaintext version from your HTML email and allow you to review and edit that plaintext version. It’s a good idea to use them. If my service is having trouble getting through to my contacts’ servers, for example, it will offer only the plaintext version on its final delivery attempt.

Take-Away Points

Remember, anywhere from 25% to 50% of your email opens are going to be on mobile devices from here on out.{7} So be sure to add the following best practices (plus the ones we discussed in Part I of this series) to your email marketing toolkit:

1. Keep file sizes small.
2. Size images with mobile in mind.
3. Plan for an images-off environment.
4. Use short, front-loaded subject lines.
5. Make the most of pre-header space.
6. Make it easy to click.
7. Consider adding click-to-call.
8. Provide a plaintext version.

Next Steps…

Need content for some new, mobile-friendly email campaigns?

Call CopyEngineer at (+39) 011 569 4951.

Or drop me an email at:


{1} Knotice Mobile Email Opens Report: 2013 Overview, IgnitionOne and Knotice LLC, 2014.

{2} Email Interaction Across Mobile and Desktop, Campaign Monitor, 2014.

{3} Arvind Jain and Mustafa M. Tikir, Is the web getting faster?, Google Analytics Blog, April 2013.

{4} Simic, Bojan, The Performance of Web Applications: Customers Are Won or Lost in One Second, November 2008, Aberdeen Group.

{5} iOS Human Interface Guidelines, Apple Inc., updated October 2014.

{6} Hodgekiss, Ross, Email, phone home: Initiating voice calls from HTML email newsletters, Campaign Monitor, October 2011.

{7} Cole, John, How to Optimize Email for Mobile – Part I: 7 Best Practices, CopyEngineer, Novemberr 2014.

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