How To Write Email Subject Lines: 9 Best Practices 

Many of them are probably from ecommerce sites, just like yours. From deals, to newsletters, to welcomes, and policy updates, there’s a lot to sift through. 

Think through your own email habits. Are most of those marketing messages getting opened? Read? Probably not. So when you do take the time to open a marketing email, what’s the differentiating factor that sets it apart from the rest? Chances are, it’s the subject line that draws you in. 

The cliche is true: you only get one chance to make a first impression. Your subscribers will judge your email based on a fleeting glance at your subject line in their inbox. You already poured your time and effort into crafting a brilliant email marketing campaign; you don’t want it to be ignored (or worse, deleted.

Even the greatest marketers sometimes get tripped up while writing subject lines, so don’t sweat if you fall into that category. Fortunately, there are a few proven formulas you can follow to craft subject lines that catch your subscribers’ attention. Let’s dive right in.

  1. Include Preview Text

A great subject line is composed of two parts: the subject line itself, and the preview text that follows. Preview text is the little snippet of copy at the beginning of your email that appears next to the subject line or under the sender in the recipient’s inbox.

When crafting a subject line using the following tips, also be sure to keep in mind engaging preview text. Together, these two create the pretty packaging that your email is wrapped in.

  1. Be Concise

A frequently asked question is, “How long should my subject line be?” And while there’s no cut and dry answer, studies have found that subject lines in the range of less than 65 characters (or five to nine words) tend to be most effective.

Our Customer Success team actually loves the formula “3 Seconds. 3 Words.” when it comes to writing great subject lines. Your email is (hopefully) hitting lots of eyes, so try to use simple language that can be easily understood by the largest possible audience. Now’s not the time to bust out your SAT words.

Remember, you only have your readers’ attention for a few seconds (if that), and sometimes less is more.

  1. Get To The “What’s In It For Me” ASAP

Your subscribers will be reading your emails on multiple different devices, including mobile, which shows fewer characters of your subject line. Make sure the most important information is visible, no matter the device, by putting it first.

One of my go-to practices for any email I write, whether it’s marketing-related or not, is getting to the “what’s in it for me” for my audience. Show your recipients immediately what’s in it for them if they open your email. Perhaps it’s a great deal, a solution to make their lives easier, or new products they’ll love. If they don’t see the value in it for themselves, they’ll probably delete it.

  1. Ask A Question

Human psychology dictates, when you ask a question, someone will try to fill in the blanks with an answer. Asking a question of your readers will buy you a couple of seconds of their attention as they consider what their response is. It can be a completely hypothetical question, inspired by what you’re selling. Just make sure it actually relates to the content of the email.

Similarly, you can set your subject line up as a teaser, like having it be the first part of a trivia question, fun fact, or riddle, so your readers need to open the email in order to see the rest.

  1. Create Urgency

Everyone is susceptible to the fear of missing out, or FOMO. Use this fear of regret to drive urgency for your readers to open your emails, click, and hopefully buy. Whether you’re alluding to product scarcity or a limited-time offer, giving your audience a deadline or a sense of belonging if they engage is a surefire way to grab their attention and seal the deal quickly.

  1. Use Command Words

Another quick psychology lesson for you: people respond positively to clear, direct instructions. Using command words in your subject line straightforwardly points people to the action you want them to take. Words like “get,” “buy,” “look,” and “shop” are short, yet effective.

  1. Use Numbers (And Emojis)

Give your readers a good idea of what’s included in your email by being as specific as possible, including any relevant sales or discounts in your subject line. This serves the dual purpose of immediately informing customers about the reason for your email, and enticing them to open it to get that sweet deal.

Numbers and emojis also serve the purpose of breaking up text, making it even more digestible for a quick scan. Plus, emojis are a fantastic opportunity to exercise your brand voice, and make your emails feel a bit more personal. 

  1. Personalize (And Have Personality)

Gone are the days of overly formal email jargon. Talk to your recipients like they’re old friends (especially since they’re probably more likely to open an email if it’s from a friend). In fact, it’s estimated that personalized subject lines improve click-through rates by an average of 14 percent.

You can include your subscriber’s name in the subject line, or take it a step further by using list segmentation. This allows you to personalize emails based on customers’ data you’ve collected through previous transactions and onsite popup forms.You may choose to send particular messaging to new customers, existing and loyal customers, serial browsers, customers interested in a particular type of product, or customers within a particular geographic area.

It also might help to personalize yourself; for instance, I receive emails from Elisa at The Baconer, rather than just The Baconer – and now I feel like I know Elisa. I’m a vegetarian, but I always open her emails.  

Whatever you do, stay away from generic subject lines, like July Newsletter. Would you be tempted to open that email? No? Didn’t think so.

  1. A/B test

Not sure if these ideas will work for your brand? A/B test them, by splitting your email list into two halves and sending each an identical email, with one key difference in the subject line. Observe the statistical performance of each and use this data to improve.

Takeaway: Subject lines are important, but don’t have to be scary.

Your subject line is just as important as the content of your email itself. It acts as the sparkly object that draws your readers in.

You can steal the examples we showed you and make them your own. But the ultimate way to get subject line inspiration is by paying attention to those of the emails that catch your eye in your own inbox!

You want your readers to open your email, engage with your brand, and hopefully make a purchase, and the subject line is the first step.

Privy is a Boston-based business offering a suite of email capture and conversion tools, including exit-intent driven website pop ups and banners to grow email lists, reduce abandonment and drive sales from a website or online store, without any coding or development skills needed. Read more at