Email Subject Lines: Specific Is the New Short

5 min

For years now the best practice for writing email subject lines has been “keep it short”. This became even more important when more and more people started reading their emails on mobile devices. But – when you look at the data – does this advice really hold true? I have numbers that say something a little different.

As an email marketer I’m sure you know that many email clients cut off subject lines in the preview pane at 40 characters or less, and mobile devices can be even more limiting. So all best practice advice for years has been based on that: we’ve been told to keep our subject lines short. Or at least put the most important information first – which actually still makes a lot of sense, and I won’t argue with that. But according to the data from our recent research study, short subject lines are not the ones that are the most effective.

They’re certainly the most common – the majority of the subject lines of the emails we examined were 30-39 characters long (and mind you, we examined around 2 billion emails from the GetResponse database sent in Q4 2016, all over the globe.)

Email Subject Lines: Specific Is the New Short

Enter open and click rates.

Editor’s note: If you’re looking for fresh data and statistics, check out the all-new Email Marketing Benchmarks report.

What we’ve noticed was the fact that the subject lines that got the highest open rates were 90-119 characters long. Not something you’d call a short subject line, right?

Same goes for click rates – the research found that click rates are also the highest for longer subject lines (130-139), with the most popular length somewhere in the middle.

Email Subject Lines: Specific Is the New Short

What does that mean?

The fact that a subject line is short enough to not get cut off by email clients doesn’t make the email more likely to be opened. In fact, the length of the subject line doesn’t seem to be the crucial element here at all. According to Kath Pay, it’s about being specific. Specific subject lines naturally tend to be longer – they include more detailed information, while short subject lines tend to be generic and vague (after all, how specific can you be in 30 characters?)

Some studies show that 35% of recipients open their emails based on the subject line alone – and it seems only logical that the more specific information you include, the more you can get your audience interested with the  details, such as dates,  price, or elements of personalization.

Of course, this is just a theory based on the data, and we’d have to test specifically (sic!) how specific subject lines perform in comparison to general ones. But it’s a completely valid theory that I think is worth exploring. And the data proves one thing for sure – take best practice advice with a grain of salt, and test. Testing is the only way you’re going to see what works best with your audience.

What about the preheader?

The preheader still tends to be undervalued, or even overlooked (probably why it’s my favorite element of the email.) In our research study, only 13% emails included it. It’s a shame, because the preheader is your chance to build on the subject line and add more information, if you can’t/don’t want to be too specific in the subject line itself. Even if your subject line does get cut off in the preview pane, most email clients will display the preheader – so why waste that little piece of text?

Email Subject Lines: Specific Is the New Short

When you look at the open and click rates – guess what – both are higher for emails that included preheaders.

Email Subject Lines: Specific Is the New Short

It’s worth noting that preview text and preheader might not be the same thing. Preview text will play a similar role if you’re not using a preheader at the top of your email – displaying along with the subject line in the email envelope – but it may be hidden in the body of the email. If you’re omitting the preheader/preview text altogether, the first line of text within the body of the email will take its place (so bear than in mind when writing it.) Watch out – it might be the alt text or title of your header image, if there’s no other text preceding it.

Of course, I’m not talking about the “View your email online” type of preheader here. (I can’t really see how it can influence anyone to open the email.) But if the preheader continues or complements the subject line (or: is the next element of the story you’re telling in your email), then it’s another, well, story altogether.

About the story: tell it, don’t sell it.

Today marketing is very much based on storytelling. In an email, you can start your story in the very subject line. Use it to set the scene, and make it interesting enough for people to click. And when you’re doing that, remember that the rest of the email has to deliver on the promise you’re making in the subject line. Your open and click rates will thank you.

Now back to the main topic.

Back to “specific” – some examples.

So I browsed my inbox (or inboxes) in search of some subject line + preheader/preview text duos. Take a look at a few I found. They’re not necessarily short, but they give me enough information to decide if I’m interested in the email (even if the subject line’s cut off, I can still make sense of them.)

Like this one:

Email Subject Lines: Specific Is the New Short

And here’s the same email seen in the Gmail iOS app, which cuts off the subject line text pretty heavily, but still lets me understand what the email’s about.

Email Subject Lines: Specific Is the New Short

Or this one, which gives me pretty detailed info in the preview text.

Email Subject Lines: Specific Is the New Short

With a totally unspecific subject line, this email does a good job using preview text to let me in on the details (free shipping!)

Email Subject Lines: Specific Is the New Short

Similarly to this one, explaining the event mentioned in the subject line.

Email Subject Lines: Specific Is the New Short

This one combines a functional preheader, sending the reader to the online version, with extra information that’s added to the subject line.

Email Subject Lines: Specific Is the New Short

This on the other hand, shows the completely wasted preheader opportunity:

Email Subject Lines: Specific Is the New Short

Along with this one that’s completely missed the specificity boat – both by being vague in the subject line, and completely ignoring the preheader/preview text:

Email Subject Lines: Specific Is the New Short

Nope, I didn’t open it.


Your audience doesn’t care much about how long, or short your subject line is. So when crafting (and testing!) your next subject lines, remember to take into account much more than the length of your subject line. Put on your subscriber’s shoes, and read it in different email clients/on different devices. Check how the preview text plays off your subject line (does it?) Would you open your email?

Over to you

What worked for your subject lines? Got any advice? Let me and others know in the comments.

Karolina Kurcwald
Karolina Kurcwald
Karolina is a brand messaging consultant and copywriter for SaaS and B2B tech. She helps brands clearly define what sets them apart from the competition and communicate it in a way that resonates with their customers. As a career coach, she also helps people in the creative and tech industries find and communicate their value to potential employers. Catch her at: