10 ways to write a killer email subject line

If you’re like us, you’ll get hundreds of emails land in your inbox a day.

Messages from staff, sales pitches, automated email flows… the list goes on.

This means you need a powerful, effective subject line to stand out from the crowd.

64% of people decide to open an email based on the subject line alone. So if your subject line is vague, spammy, or just plain confusing, you run the risk of your message not getting read.

Want to write email subject lines that get results? Here are ten great ways to get started.

Article topics

1. Know your audience
2. Ask a question
3. Don’t make it spammy (unless your customers want you to)
4. Keep it short and sweet
5. Use personalisation
6. Evoke emotion
7. Call on FOMO
8. Add numbers
9. Write your subject line last
10. Test, test, test (and test some more!)

1. Know your audience

Before you start drafting your email campaign, you need to understand exactly who you’re sending it to.

This will give you a valuable steer when it comes to crafting your subject line.

For example, a subject line like this might work for younger audiences but might leave older customers scratching their heads:

Think about:

• What pain points does your target audience have, and how can you help solve them?
• What language, jargon, and slang does your target audience use?
• Does your target audience appreciate humour, and if so, what type?
• Will your target audience appreciate emojis, and if so, which ones?

Remember that while it’s okay to use emojis in email subject lines, they can be highly subjective. For example, the OK hand emoji (👌) might be a positive sign in the UK and the US, but can be offensive in other countries.

Creating a customer profile is a great starting point, and you can use it across your other marketing campaigns too.

2. Ask a question

The easiest way to get your customer’s attention?

Ask a question. This doesn’t just encourage them to engage and read the rest of your email but invites them to share their thoughts – making them feel valued.

Plus, asking a question can keep your email subject line neat and concise, which we’ll look at the benefits of later.

3. Don’t make it spammy (unless your customers want you to)

People only open emails that they consider trustworthy. If your subject line sounds suspicious, prospective customers will ignore it or, even worse, report it as spam.

As a general rule of thumb, try to avoid the following:

• Overusing emojis, question marks, and exclamation marks
• Spammy words like ‘cheap,’ ‘jackpot,’ or ‘earn’
• Subject lines in all capital letters
• Using ‘re:’ to imply a customer has already read your message

However – rules are meant to be broken, and it may be that your prospective customers like lots of exclamation marks, tons of emojis, and words in all caps. Your decision ultimately depends on what you sell and who you’re selling to.

Are you excited about an upcoming flash sale? Go all out. Trying to sell funeral cover to customers? You might want to give it a miss.

4. Keep it short and sweet

About 55% of emails get opened on mobile devices. This means that if your subject line is long and rambling, there’s a chance it might get cut off.

Even if your customers only open your emails on desktop, it’s still best to get to the point. Your email recipients will only scan your headline for a swift second or two before deciding whether to read on.

In my experience, it’s best to keep your subject line to about 50 characters – roughly seven to ten words. That might sound like a lot, but when you need to tell prospective customers what your email is about, it can be a challenge!

We recommend top-loading your subject line – put the most critical information first. That way, if someone is on their phone and your subject line is truncated, they still get the gist of what you say.

It’s also okay to be direct – you don’t need to use full sentences. Some of the highest-converting subject lines I’ve seen have consisted of just a few words.

Here’s a tip if you’ve got a lot to say – use your preview text. This appears for the majority of email clients and is a great way to provide extra information to customers.

5. Use personalisation

You want your subject lines to be as targeted as possible. When you’re not in a position to write a unique email subject line for every subscriber, personalisation is your new best friend.

With personalisation, you’re using the data you have on file to create a subject line that directly speaks to each individual recipient. Just add a tag to your subject line, and your email marketing tool of choice will fill in the gaps.

The easiest way to use personalisation is by adding a name to your email subject line – this can increase your open rate by over 50%!

Of course, there are other methods you can take advantage of too. For example you can:

• Mention previous products or services they bought
• Refer to a person’s local branch of your business
• Drop the name of the company they work for

6. Evoke emotion

When your customers read your subject line, you’ll want them to react in a certain way. Excitement that you’ve just launched your sale, frustration that you’ve sold out of a particular product, happiness that you can help them solve their problems.

By choosing the right combination of words, you can nudge your readers into consuming the rest of your email.

Take this email subject line for example – it exudes warmth, friendliness, and appeals to readers who want to sip hot chocolate and snuggle on the couch.

On the other side of the spectrum, we have this subject line, which uses a well-used Anglo-Saxon word to make customers feel a certain way.

(As an aside, swearing in email subject lines can be a good way to grab attention. However, you need to make sure your target audience is 100% on board, and take steps to make sure your email doesn’t get trapped in the spam filters.)

The best way to evoke emotion through your subject lines are through ‘power words’ – a list of words that trigger a specific response. Understand how you want your target audience to react, and use the right words for the task.

Emojis can also help evoke emotion in your readers, but as stressed in point one, do your research to make sure your email recipients won’t take them the wrong way.

You want customers to buy your products, not hit unsubscribe.

7. Call on FOMO

The ‘fear of missing out’ (or FOMO) is when you think you’re not in the know about specific events and experiences.

When done right, it’s a great way to get people to read your emails and convince them to convert.

FOMO is all about tempting email recipients into quickly checking out a specific deal or offer with the risk that if they don’t, they won’t be able to take advantage.

You can incorporate FOMO by:

• Adding timescales to your messages – ‘sale ends at midnight’
• Implying scarcity – ‘only 10 kits left – don’t miss out!’
• Using social proof – ‘see why everyone is loving this dress’
• Promoting urgency – ‘you only have 24 hours to buy’
• Suggesting limited availability – ‘once they’re gone, they’re gone’

Bear in mind that you can have too much of a good thing with FOMO. Use it too much, and you can end up annoying customers.

Save it for when you want to give your email marketing campaigns a big push.

8. Add numbers

Whether you’re writing cold email pitches or promoting your latest eCommerce store sale, a number in your subject line can work incredibly well.

Firstly, it drives curiosity – recipients will want to click your email to find out more.

Secondly, it can make your subject line clearer and more direct.

Finally, it shows you’re trustworthy and that you’re using data to back up your claims.

If you choose to use numbers in your subject line, it’s best to keep things simple. Stick to one number and avoid anything that requires prospective customers to do complicated mental arithmetic.

9. Write your subject line last

Writing a good subject line is hard. There are times that I’ve written ten, twenty, even thirty different subject lines for an email and none of them fit right at all.

One of the best ways to determine the ideal subject line is to create it after you’ve written your email copy.

This might sound a little counterintuitive. However, as you’ve already done the groundwork and determined what you want to tell your customers, it makes it a lot easier to generate ideas.

10. Test, test, test (and test some more!)

Email marketers never, ever rest on their laurels. They’re constantly making changes to the emails they send out to see which magic combination of words and images drives the best results.

Even a small tweak like using a different emoji or switching to sentence case can have a major impact.

Regular testing and implementing changes will give you a solid indication of what subject lines resonate with your target audience the most.

Many email marketing platforms offer A/B testing functionality. You create the same email campaign with two different subject lines, send half your subscribers each email, and see which one leads to the highest open rate.

In conclusion: don’t make your email subject line an afterthought

Think of your email subject line like a shop window display. You want to make it enticing and show what you can offer, so prospective customers want to enter your store.

Get your subject line right, and you’re one step closer to getting people to convert.

It pays to invest time in crafting the perfect email subject line. In fact, we often spend as much time drafting a subject line as we do creating the whole body of an email.

Still need some inspiration? Try ActiveCampaign’s email subject line generator. Choose your email type, enter a keyword, and it will give you some subject line ideas to play around with.

Need help with your next big eCommerce project? Find out how we can support.

Excellent email marketing is our speciality at Xigen – there’s nothing more satisfying than creating emails that drive leads, enquiries, and sales for our clients!

If you’re interested in transforming how you market your products and services to customers, here’s some additional reading you’ll enjoy:

• Five simple hacks to transform your email campaigns
• Four easy ways to grow your email list
• What time should I send my email campaigns?

And, of course, if you’d rather an award-winning digital marketing agency did the hard work for you, just get in touch.