How To Write The Perfect Email Subject Line

Learn how to write the perfect email subject line.

As in real life, first impressions matter in email marketing. Do you want to be the cool guy walking down the road everyone turns around to look at, or just that creep in slippers and a leopard-print bathrobe most move away from when they cross paths in the street?

The inbox is a noisy and crowded place, and the fight for your contacts’ engagement is on. You have around 60 characters to capture your consumer’s attention in the subject line. How will you do it?

There have been a ton of studies and debates posted on the web, arguing what phrases and power words produce higher open rates. Here, we’ll cherry-pick the words, combinations, and formatting of different subject lines, to help you write the best one to match your company’s brand voice and goals.

Email subject lines that don’t suck

Sounds like a good starting point, right? We’ll give you the key points on how to achieve this, but to see how these techniques look like in action, here are a few subject lines we’ve come across that have stood out in our inboxes.

Here we see the correct use of consistency. Morning Brew has found a relevant emoji and has stuck with it to make their emails recognizable in the inbox. They keep their subject lines short to just pique our interest without giving much away.

This subject line tapped into our curiosity and FOMO (Fear of missing out) at the same. It made us think: “Who did? What does the album sound like? Why is it special? I need to know!”. The email included a description of the ablum, with CTAs to learn more, as well as explore more on the Pitchfork website. The catchy subject line was not click-bait at all, it delivered on the little promise in the intriguing subject line.

We’ve been going on and on about emojis for quite some time now. Do they work? Which one’s best? We’d done a ton of research on the matter and have shared our findings with you. Maybe you’re not as excited to see them spread through the cyberspace as we are, but come on, they’re pretty cool. Here we see how Product Hunt uses them in a relevant context, creating a nostalgic feeling of mid-1990’s computer games.

Vidyard opens up with a play on words with a little bit of tongue and cheek as well. When it came to this email, you can see that they’re promoting their product to imporve your video strategy. They know you want to imporve your metrics, and opening this email is going to give you the information you need to do so.

Four top tips for killer email subject lines

When it comes to constructing your subject line, there are three things you should always consider and follow like a ritual.

Length matters in email subject lines

The verdict is still out on whether shorter subject lines drive more opens. A shorter subject line may be more likely to catch the reader’s attention, but it still has to be reflective of the content inside. As the subject line contains less detail on the content, the user might not find what’s inside the email interesting after having curiosity drive them to open it.

Additionally, you should be aware of each email client’s subject line preview length. For example, Gmail only shows the first 70 characters, where Hotmail / Live and Yahoo Mail show 60 and 46 characters respectively. Do some research on different mobile clients to find out the current limits too.

Tone and voice

Positive or negative, questions or exclamations, vague sentences or more direct ones, FOMO, urgency… There are many ways in which we can communicate one same idea and playing around with different options might keep your emails fresh and enticing. However, your subject line (and your content) should always be aligned with your brand voice and tone. Having a recognizable style will go a long way.

Beta-i’s newsletter does a great job at creating attractive subject lines that are unique to them, and is perfectly consistent with their brand voice. Have a look a some of their recent newsletters below.

P.S. Noticed how they use someone’s name as their From Name? This also contributed to their overall brand voice. Find more on From Names here.

Symbols and emojis in email subject lines

Marketers have been using hexadecimal symbols for a while now, but they are not as widely used as you would expect because they are not compatible with all email clients. Same happens with emojis: not all email clients and devices work with these either. Whether you decide to opt for one or the other, they should always be used in context, otherwise it can have a bad effect on your brand and be seen as childish.

Testing

Lastly, always A/B test. You can’t 100% know which subject line will work best, so set up an ‘A/X test’ to try out up to 10 different subject lines. For example, you might want to send your campaigns on Tuesday at noon with an A/B test in place and let it run for 20 hours, and then have the winning subject line and email be sent early on Wednesday morning so it’ll be one of the first in your recipients’ inbox when they get to work.

After A/B testing and sending a couple of campaigns, be sure you use ‘Campaign Comparison’ to see which campaigns worked best for your data-set and look to improve future ones! By comparing your results with your industry benchmarks you can always have specific goals to aim at and improve your email campaigns over time.

Seven things to test on your email subject line

Speaking of testing, how many different things do you usually test in your email subject lines? Do you focus on your wording, your tone or the message itself? If you’ve answered one of the three, you’ll only be “partially correct”. The truth is you definitely need a combination of the three to ensure you find the perfect one for each campaign.

Length:

This is one of the most basic tests in some people’s eyes, but really something to look into. The subject line length allowed by different email clients and devices varies from around 70 characters on Gmail’s desktop version to just 30 characters on some of the smaller Android phones, so understanding this will help you pinpoint how long is too long.

But there’s another element to the length that a test will allow you to understand better. Do your readers feel intrigued by subject lines they can’t fully read? Or do they find this irritating and prefer shorter, more precise subject lines? Try a range and analyze the performance, both for each individual campaign, but also across different email clients and devices over a period of time.

Personalization:

Another basic one, but yet another one that can be easily overlooked. Does your audience react better when they see their name used in the subject line? We keep on talking about the importance of personalizing content to make it more relevant, but at the end of the day, your contact list is formed by a unique set of people with their own particularities. It could be that someone sends them a daily influx of messages with personalized subject lines, and they just instantly associate it with some unwanted marketing campaign that they automatically ignore.

Emojis:

To emoji or not to emoji? For today’s email marketer, that might actually be the question. The suitability of emojis will depend on your database’s age and location, their use of social media and even the device they read their emails on.

But it’s not just about whether to use emojis or not, but also which ones to use. Different cultures might react to the same picture in different ways and, no matter how many times they try to convince us, a peach is not always a peach.

Negative Statements, Questions & Exclamations:

The tone, the wording and how you phrase your subject lines will definitely have an impact on how your readers’ willingness to open your emails. You could be stating facts, sharing excitement or asking them a question to make them reflect on something. Maybe highlighting great things works best, or maybe your readers are more inclined to open emails that stress negative elements.

Would a salary comparison page get better results with the negative statement “You’re not being paid what you deserve”, the question “Are you being paid what you deserve?”, or an exclamation such as “We know how much you should be making!”? The only way to know is by testing.

FOMO / Clickbait:

Fear Of Missing Out is a thing. It is the psychological principle that rules Facebook: people want to know what other people know, what other people are talking about. Curiosity meets insanity, basically. So, are you leveraging your contacts’ FOMO with subject lines they just can’t resist?

To an extent, the basis of clickbait subject lines is precisely this overwhelming curiosity that pushes us to open a message to find out if, in fact, “there’s no way I can imagine what this person said”. Clickbait headings are all across the Internet nowadays and people are slowly catching on, but you’ll never know if they work with your audience unless you try them.

Vague / Straightforward:

You’ve probably heard about Obama’s email marketing success during his 2012 presidential campaign. Well, a big part of this was down to the interesting range of email subject lines his team picked, which caused impressive open rates and an all-time fundraising record. The team tested a huge number of subject lines, varying from straightforward messages such as “Thankful every day” or “Some scary numbers” to more vague ones, like “ Change”, “I will be overspent” and even a friendly “Hey”.

Discounts & Urgency:

Another interesting idea worth investigating if your company sends product emails is to see whether outlining discounts and promotions, or creating a sense of urgency on your subject line will generate higher open rates. Overusing time-limited campaigns and headings might become a bit like the tale of Peter and the Wolf, where your contacts stop trusting you and end up not reacting as you’d wish, because they know another offer will be coming their way soon. Be sure to test this frequently to find the right balance.

There’s no limit to the things you can test. We’ve covered just a few of the possibilities here, but there are many more you can try. Want to find out if including the name of your brand in the subject line makes people recognize you more and be more willing to open your email? Try it. Think that including a profanity might generate some interest and spice up your contact’s dull inbox? Try that too! At the end of the day, finding the perfect subject line requires a bit of both art and science.

With all that said, now it’s time to get to work! Share your best performing headings and your most interesting examples with us on Twitter.

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This blog post is an updated version of the post “How To Write The Perfect Subject Line“, published on the Mailjet blog on March 23rd, 2015 by Amir Jirbandey.