dark mode experiment icons

How Popular is Dark Mode Usage for HTML Emails?

Is dark mode for HTML emails a passing trend, or is it popular enough that teams should consider it as they design, develop, and optimize campaigns?

According to a survey from Pathwire and Ascend2, 44% of marketers are considering dark mode during email production. Another 28% have plans to start. But what about your list and your subscribers?

It’s a tough question, and it’s one we’ve been trying to answer since we launched our Darktober dark mode exploration last year. Finding out if your subscribers view emails in dark mode isn’t easy. But I was up for a challenge! That’s why, over the past few months, I’ve been running a dark mode email experiment.

UPDATE: Email on Acid now offers dark mode open tracking inside our application. Find out how many subscribers are viewing campaigns in dark mode on specific email clients.

A test for dark mode HTML emails

Email on Acid CEO John Thies and I had a couple of conversations on the best way to potentially pull this off using our email readiness platform. In the end, we decided on a method I call The Dark Mode Pixel Hack, which involves the use of carefully placed analytics tracking pixels.

If you’re interested in trying an experiment like this with your own campaigns and subscribers, we’ve put together a How-to PDF for the Dark Mode Pixel Hack.

Check out the infographic below to see the results of our experiment, which took place during the last few months of 2020 and involved six different campaigns.

dark mode email test results graphic
Click to view a larger image

Breaking down the results

I was a bit surprised at just how many of our subscribers really are opening our emails in dark mode. Part of me originally wondered if the percentages would be low because dark mode is still fairly new. In fact, similar studies from others in our industry revealed even higher numbers.

Our audience may be part of the reason. Developers are more likely to use dark mode to help with eye strain, which means they could be prone to viewing email in dark mode too. However, out of subscribers on our lists for whom we have the information, only about 25% of them identified as developers.

One very important thing to keep in mind is that the hack I used to conduct this experiment only works with email clients that use WebKit as a rendering engine. That includes major clients like Apple Mail and Outlook for Mac. But Gmail and Outlook for Windows do not use WebKit.

Despite a bit of a blind spot, it can be assumed that a decent percentage of the “Unknowns” in our experiment are also using dark mode for email. After all, Gmail users have had the option to try dark mode since 2019. Our test results make it clear that a significant segment of Mac users prefers dark mode. I’d also expect the use of dark mode to continue climbing as the trend continues and more people choose to adopt it.

The bottom line on dark mode email usage

If at least 10% or more of your subscribers are using dark mode, you could be losing out by failing to optimize for that sort of user experience. Designing and developing emails with dark mode in mind improves your chances of getting your entire list to engage with your campaigns.

Looking for more content on dark mode for email? Check out our dark mode infographic, read about the debate over dark mode vs. light mode, and watch our webinar, Designing Emails for Dark Mode, where I give some advice along with two other experienced developers.

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