This article provides some best practices for adding emojis and symbols to your subject lines.

Due to its unique location, the subject line is considered to be the most important sentence of your email campaign. Several studies have shown that using a symbol or emoji in your campaign's subject line to call attention to your message can also increase open rates when used effectively, though it differs based on industry. Because we know how fun and enticing emojis can be, we've compiled a quick list of best practices you should adhere to when using them.

5 Best Practices for Using Emojis in Subject Lines

1. Know Your Audience

Subject line emojis can be fun and on-trend, but they are certainly not appropriate for all brands. In many industries, an emoji can easily come off as unprofessional, so it's important to think about both your brand and your audience when deciding whether or not to use an emoji.

2. They Serve a Purpose

Any emoji or symbol you use in your subject line should also be relevant to your content. Meaning, it is not a good idea to use them solely to capture the attention of your audience, instead, use them to enhance your brand or content.

3. Use Them Sparingly

The subject line is not only prime real estate, but it's also a very limited space. So be sure that when you are using emojis, it's to add value to your subject lines because overdoing it could easily be interpreted as spam.

4. Test Them Across Platforms

An essential element of using emojis and symbols is testing them to know how they display across various email providers, operating systems, browsers, and devices. One size does not fit all in this scenario. Apart from sending yourself or your associates a test of your campaign before sending it out to the designated audience, it's a good idea to check an emoji library like Emojipedia to see how the symbol or emoji you are using looks on different devices.

5. A/B Test to See What Your Audience Prefers

A great way to find out what a specific audience prefers is to conduct a subject line split test. This can help you determine if one emoji performs better than the other or if not using an emoji at all performs better than using one.

Our Emoji Test

As an example, we decided to recreate the steps our users have taken to find and use an emoji in a subject line. To do so, we used the pizza emoji from this Facebook symbols site and tested how it looked across different platforms. We simply copied the emoji and pasted it into the subject line field like this:

After testing, we found that the emoji looked vastly different across platforms. In some cases, it failed to render at all. In other cases, the emoji rendered, but as a black and white image instead. This occurred in nearly every version of Outlook on the Windows 10 OS.

In the majority of platforms that we tested, the emoji rendered in color, but looked significantly different than the version from the Facebook symbols site. This isn't particularly surprising, but it's an important reminder that the emoji that you choose, may not be the emoji that your contacts see in their inbox.