7 Tips for Writing Better Email Subject Lines

by Email Marketing

Email marketing is dead.

Yet, here we are.

About to talk about email marketing.

The truth is, email marketing is far from dead. In fact, if you’re thinking about using email marketing in your business (you should be), consider the following stats:

  • 73% of millennials identify email as their preferred means of business communication.
  • 80% of retail professionals indicate that email marketing is their greatest driver of customer retention (social media trails behind at just 44%)
  • On average, “Welcome Emails” are responsible for 320% more revenue on a per email basis than other marketing emails.

Ok, email marketing isn’t dead

Let’s all agree right now, email marketing isn’t going anywhere.

It’s growing and it’s going to continue to grow whether you’re on board or not. The good news is, it’s definitely not too late to get started using email marketing, so get on board.

How to write email subject lines that get opened

An email subject line has ONLY ONE GOAL: to get the reader to open the email. Period. Full stop. 

The truth is, we skim our inboxes so standing out from the crowd is essential.

We’re all guilty of it. It’s how we’ve been trained, thanks to the barrage of emails we receive on a daily basis. Skimming email subject lines while scrolling and gratuitously smashing the “delete” button is a necessary evil.

It’s a survival skill.

Pictured: anyone with an email account going through their inbox.

The indecisive weak among us get buried under the crushing weight of an impossible graveyard of unread emails. (I know – pretty dramatic, right? I should write novels.)

In all seriousness though, I asked everyday people on social media to screenshot their number of unread emails. The following are some of the responses I received. This is what you’re fighting through.

It’s because of this universal inbox truth that I’ve compiled a list of tips all designed to help make sure your emails:

  • avoid the spam folder
  • get opened AND read

Let’s get to it – here are the tips.

1. Keep your subject line to less than 50 characters

There isn’t a direct correlation to the open ratio vs number of characters in a subject line. However, most emails are read on mobile devices and if your subject line takes too long to read, it will get canned for sure.

28-39 characters seems to be the sweet spot but definitely shoot for less than 50 characters to make sure your subject line isn’t truncated or hard to read.

Here is a screenshot of my inbox on my phone this morning:

The first email from the Daily Stoic (awesome site by the way, highly recommend it) does a great job of catching my attention and keeping their subject line from being truncated.

Even the email from Inner Warrior Apparel  is spot on. “Happiness in 10 seconds.”  It’s short, to the point and interesting.

The subject lines of the Michael Hyatt and Jeff Bullas emails are both truncated on mobile at unfortunate places.

They’re cut off right at the point where the sentence might start to make sense but on mobile, I’m not entirely sure what I’m getting when I open those emails.

2. Convey a sense of urgency

Urgency or “fear of missing out” (FOMO for the marketers out there!) is an old sales strategy that is still around today because it works. We have an deep rooted, evolutionary fear of being left behind.

Phrases like “24 hours left” or “ending today” work great to accomplish this, especially when talking about special offers or sales.

Just like anything, however, this strategy should be used in moderation. If all of your emails feel “urgent” your readers will likely start unsubscribing because they don’t want to always feel anxious when they see your email arrive in their inbox.

3. Words you should avoid using in your email marketing subject lines

The following list of words should be avoided when writing your subject lines. The words should be avoided because you’ll come off looking spammy, desperate, clueless or all of the above.

If you have to use one of these occasionally it’s not the end of the world but avoid when you can and look for synonyms when possible.

  • $ (in any quantity $$$$)
  • Discount
  • Free
  • Guarantee
  • Quick call?
  • Re: (this one annoys me to no end. These all get automatically deleted)
  • Sale
  • WIN

4. Be clear about the value of the email

While being vague can pique a reader’s curiosity and can work sometimes, it’s a dangerous game to play.

If you make your reader feel even slightly deceived you’ve likely lost them forever.

Why? Why would you lie to me? I subscribed! I SUBSCRIBED!

Unless you’re specifically sending emails to the Hardy Boys (probably just dated myself there) don’t make the subject line a mystery. Whatever the topic of your email is about, allude to it in the subject line.

Not Pictured: a responsible use of my time.

You don’t have to give everything away in the subject line but let the reader know WHY they should open your email.

Along these same lines, don’t promise anything in the subject line that your email can’t deliver on.

MailChimp conducted an email subject line study and found that short, clear subject lines performed better than vague or cheesy statements.

5. Ask a question

Asking a question is a good way to get a response, especially if it’s a question that creates what’s called a “curiosity gap.” A curiosity gap is the space between what we know and what we want or even need to know.

Here’s an example of a curiosity gap: What diet mistakes are you making?

99% of us could be eating better and we accept that, but if someone is willing to tell us where we’re messing up, we’re happy to learn. We want the easy solution.

You can find no less than 380,000 more examples of the curiosity gap on Buzzfeed.com if you’re looking for further reading.

6. Sentence case vs title case

There is a lot of debate about whether email subject lines should be written in Title Case, “Where the First Letter of Each Word is Capitalized, Like This” or Sentence Case “Where only the first letter of the first word in a sentence is capitalized, like this.”

Personally I prefer sentence case as I think it looks cleaner and more natural but this is of course just my humble opinion. It feels more conversational, which is the tone I want when writing on the web.

Test both and see what works best for your audience.

That being said, I think everyone in the known universe can agree on this: don’t write in all caps.

Writing an email subject line in all caps is an awesome way to end up in the spam folder and look like a spectacular jerk while doing it.

7. Test subject lines

Test different subject lines and see what works best with your audience.

This is extremely important so I’ll say it again: test different subject lines.

Just about all of the major email marketing platforms allow for A/B testing – use it. Once you’re able to identify techniques that are successful for you, do more of them and continue testing and evolving.


Email marketing is a great way to control the message and the platform when communicating with your audience or customers. You just need to make sure you’re able to cut through the noise and that your message is actually heard.

If you’re interested in the psychology behind subject lines and headlines, check out this other post I wrote, 5 Types of Headlines our Brains are Wired to Click (thanks to psychology). It works equally well for email subject lines as it does for blogging headlines and includes a free download with 133 “fill in the blank” headlines you can use immediately.

Using the tips outlined above should give you a good jumping off point when writing your own email subject lines.

Have other email subject line tips or tricks I didn’t mention here? Drop them in the comments section!

Contributed by: Alex Brinkman

Alex is the owner and founder of Green Tree Media. For the better part of a decade, he has been helping organizations of all sizes create and grow their online presence and achieve their online goals. Aside from web design and development, Alex also has a passion for internet marketing, bio-hacking, motivational and inspirational quotes, giving strangers hi-fives and is pretty much addicted to obstacle course races.