How to create email subject lines for higher open rates

You could say that I’ve gone through different stages when it comes to my interest in email marketing. I started with email deliverability – why was it that some of my emails that I sent never reached the recipients and what is it that makes the junk inbox fill up? It is kind of techy (I put together a cheat sheet email deliverability on it) so now I got my eyes on something more – email marketing subject lines.

Why should we care about email marketing subject lines?

As marketers, we’re always aiming to get a bunch of clicks that eventually lead to conversions or purchases. But if nobody opens the emails, we lose those clicks. Forever. Ok, I’m being dramatic, but it is true. 64% of recipients say that they open the email based on who the email is from, but close to half of all your recipients say they open your email based on the subject line. In this post, we’re striving to reach that high open rate.

Open rate run down:
An email is counted as opened either when a recipient clicks a link in the email or when a recipient downloads the images (the latter means that the recipient has allowed images to be shown in the email or the preview of it). The open rate is then calculated by dividing the number of opened emails with the number of successfully delivered emails. Don’t forget to multiply by 100 to get the percentage.

The email open rate is calculated by dividing unique opens with delivered emails.

The average open rate vary from industry to industry but according to this benchmark study, in the open rate averaged 24.24% in 2017 for B2B.

The email subject line is our first and biggest chance at encouraging your recipient to view and then hopefully click your email. We can’t waste that opportunity, an attention-grabbing subject line is our best bet. It’s challenging though, as we only have a certain amount of characters and time (I mean, we do have the attention span of a goldfish, most of us). Let’s talk a bit about what makes a subject line successful. Hold on, peeps.


Start by picking what type of tone you want your subject line to have. There are different “tones” to pick from, and they speak to different “urges” that the reader has. In this post, I’ll list some of the most common tones and what an email subject line could look like, using that specific tone.

This is probably the most common one, as this one basically tells you exactly what’s in the email. I would say that this tone is meant to not waste any of your subscribers’ valuable time, you tell them exactly what they get up front. However, this does raise the expectations of your email content, as the subject line still needs to spark some sort of curiosity or  excitement for the readers.

Do: “4 ways to design an email”
Don’t: “Here’s our monthly newsletter”

See what I did there? They both tells you exactly what’s in the email, but all you’d get from the second option is a major snooze fest.

Valuable and/or problem solving
What value are you offering to your recipient with this email? Whatever type of marketing you do, we’re never trying to sell. We’re helping the buyer buy. Same thing goes for your email subject line. This tone speaks to the pain points your subscribers have by posing a statement on how to solve a common problem or it directly states what the readers will benefit from the email.

Do: “Never waste any more time on manual work”

Ever heard of FOMO? Fear of Missing Out; it’s a real thing and something us marketers aren’t ashamed to take advantage of because, I promise, your subscribers have it. This tone speaks to that FOMO by incorporating a deadline into your subject line. You want the recipients to feel that they just HAVE to click that email so they don’t miss out on whatever important information you had to tell them:

  • “Don’t miss out on this”
  • “Tonight only”
  • “Last chance to…”

People have a desire for closure, we need to know what happened next. This is where we take advantage of that with a subject line that works as a cliff hanger:

Do: “You can never guess what happened when I opened this email”

See what I mean? Makes you wanna open it, right?

There you have it! The first step when crafting your subject line. Pick the tone that suits your email content. You could also mix two of them, curiosity often goes very well with problem solving or urgent for instance.



Recently, I used a travel site to make a hotel reservation in Rome (beautiful city by the way, but that’s another story). After returning from my trip I kept getting emails from the travel site with subject lines that said: “Josefine, prices have dropped in Rome!” Now tell me, I just got back from there, why should I open this email? That’s right, I don’t.

What do you know about your recipients? Did they click a link? Did they perform some other action on one of your landing pages? Use that information when crafting the subject line; then the recipients know instantly that they’ll benefit from your email. If the travel site I mentioned tracked that I performed certain actions (made a reservation in this case) or if they tracked that I opened a confirmation email, a more interesting follow-up email subject line could have been “Liked Rome? Then you need to see this” referring to another destination. To automate and track who clicks on what, marketing automation is a must with endless possibilities.

What about first names? 
As you can see in the example above, they use my first name in the subject line which is a quite common way for marketers to add that personal touch. But, hold your horses for a second, this personalization debate is two-fold. On the one hand, it does strike a personal touch and there’s a bunch of studies out there that argue that it boosts the open rate. On the other hand, Benchmark recommends that you avoid first names because spam emails often contain them and therefore increase risk of recipients clicking that “mark as spam” – button.

So what to do?
There was actually yet another problem with the subject line “Josefine, prices have dropped in Rome.” That sentence was actually not all of it. The second half of the subject line read “get xx% off” but I never got to see that part until I opened the email when researching for this blog post. Don’t let the use of a name take up important space that you can use to preview your value. A name shouldn’t be your priority when crafting a subject line. The value you’re offering should be.

My two-cents on this is that there are more ways to personalize than just by name:

  • Interests and actions taken (like clicks or downloads)
  • Anniversaries (birthday emails, a year since you signed up with us etc)
  • Demographics

You don’t have to use a first name in the subject line to talk to your subscribers as a friend.


The second step is where we really get to work. To make sure that you come up with the best subject line ever, allow yourself some time to brainstorm 8-10 subject lines. I know, if you’re like me, it doesn’t sound fun – but in the beginning when we’re trying to figure out what subject lines work for us, it’s worth it. If we don’t put any time in the subject line, the email content you worked so hard on might all go to waste if the subject line isn’t enticing enough. Why not try to come up with one subject line for each one of the tones I listed above, for the same email content?


  • Length
    Unfortunately, I can’t tell you “use XX amount of characters and I swear, your open rates will sky rocket!” I wish I could. We can look at statistics but that’s no guarantee that it’s gonna work for your recipients. But fortunately, we can still look at some statistics to give us a hint as to what you should test! Ok, so here goes: Short or superlong subject lines perform the best. With 1-20 characters or 61+ characters, the open rates are slightly above average.
  • Length 2.0 – think mobile
    More than half of the emails are opened on a mobile device, which means that the email subject line doesn’t have as much space as the inboxes on a desktop. I recommend that you craft a subject line that’s no longer than 45 characters. You don’t want to do the same mistake as the travel site I mentioned, where half of the subject line didn’t show at all.
  • Use a preheader
    There’s a little trick we can use to double the limited space, and that’s with preheader. The preheader is the first piece of text you have in the email itself. That text is displayed in the inboxes as a preview of the email right below the subject line. Edit it and you can have it play nicely along with the subject line. Remember, it needs to be at the very top of the email to work. You could also use it with a transparent font so the preheader doesn’t show when the email is actually opened. You’re gonna love preheaders after this.


To protect recipients’ inboxes from fraudulent emails, there are certain spam filters in place. These filters are activated when they see an email that fulfill certain criteria (not good criteria I might add). They look at your email content and send out, but also certain trigger words in the subject line. The full list of spam words is endless, but think in terms of “free trial,” “$$$,” “fast cash” and “f r e e”. You get the picture.

Pique your subscribers interest by using a certain tone of voice. Personalise the subject line according to the actions they’ve taken, or whatever information you have on them. Use a preheader to further specify what’s in the email and to save space on the limited amount of characters. Unfortunately, there’s no golden rule when it comes to the number of characters that perform the best. You need to test to see what your subscribers like. What you should remember is that the amount of characters differs on mobile. No more than 45 characters and the email subject line shouldn’t be cut-off.

Now you, what subject lines have you seen that you feel perform the best?

As Digital Marketing Manager, Josefine oversees strategies, production and processes for all content marketing efforts, including social media, email and blog. She also introduced videos into their content marketing strategy, in which she shares her best tips on different marketing topics.

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