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How to Write an Effective Email Subject Line

You put a lot of effort into your email campaigns: want to make sure that your members open them? Our article on email campaign analytics goes into a number of ways you can check on the success of your campaign, but once you have those statistics, you still need to know what to do about them.

This article will discuss how to improve your ‘Open’ rates — that is, how often members open your emails. To fulfill that goal, we are going to explore a number of principles for writing an effective subject line for your emails.

Note that no matter how good your subject line is, though, you’ll want to make sure your members read even that part of your campaign: consult our Knowledge Base article on preventing your emails from being flagged as junk or spam.

That being said, assuming that your emails are reaching your members’ inboxes, there is a lot that can be done to make sure your members are likelier to open them. Here are a few principles of writing effective email subject lines.

Tailor It to Your Audience

Be careful and deliberate about who you send your email campaigns. Sending everyone the same campaign isn’t always a good idea: you might want to consider what you’d send a relatively disengaged member instead of ones who are active, and members who were active but have since lapsed might require a different approach entirely! How far you take this is up to you, but it’s never a bad idea to take a closer look at your audience and decide whether they’ll all react to the same content. Also, try not to send members information that is irrelevant to them, if you can help it: most people tend to appreciate personalized content, but generic content is better than sending material for a group the recipient doesn’t belong to.

Be Brief and Efficient

More to the point: be concise. You may be competing with a long list of new emails in any given inbox, and you want to make your message as convenient and effortless as possible. Effective email subject lines can’t overstay their welcome: they should be long enough to get a point across, and no longer.

Use a Call to Action

An effective subject line often pleads to the reader to take some kind of action, whether it’s to read something, sign up for something, attend something or buy something. Framing your subject in the form of a suggestion to the reader (“Act now!”) is a way to call upon the reader’s emotions, their initiative, or just their sense of curiosity.

Don’t overload your reader, though: keep it to a single call to action. Don’t spread the reader’s focus out too thinly: you’ve likely only got a few seconds to grab the reader’s attention, and giving them too much to think about in those few seconds isn’t good for keeping them interested.

Asking a question is another way to make a call to action. The reader might not know the answer but believe that it’s useful, or the question might provoke a strong emotion in the reader — inspiration, outrage, or curiosity, to name a few. Either way, it calls on the reader to react, and that might be enough to get them invested in the content.

Convey Urgency

Giving the reader a sense of something that can or should be done now is a great way to get them interested in the contents. A limited-time offer, an event whose seats are rapidly running out, a piece of information that will be useful soon — all of these situations will motivate a curious reader to investigate the email as soon as possible to determine whether they should take advantage of what they’ve learned. If a member stands to gain by replying sooner rather than later, make it clear and they’ll likely take interest.

If there’s a specific deadline involved, or you’re down to a certain number of tickets left for an event, including those specifics in the subject line can be compelling information!


Using these principles will help improve the odds that your members don’t just read your subject lines but react to them. Getting them to read your emails is the first step in keeping them engaged, so always think carefully about your subject lines.

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