Email Subject Line Best Practices: 7 Tips with Examples

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26 Aug, 2019

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It’s 2019 and by now, most businesses know that having a strong online presence and digital marketing strategy is key to surviving in the modern market. And while some things change or become outdated as time passes, others simply evolve and adapt to the new status quo.

Email marketing is one of the latter. 

Most consumers aren’t receiving daily direct mail ads and flyers anymore. At least not in the post. But we all open our email inboxes to ads, upsell emails, newsletters from our favorite brands, and coupons from companies enticing us to shop with them again.

The reason is obvious: email marketing works. As of 2015, email had an average ROI of $38 for every $1 spent. And one in five companies report an average ROI of 70:1, according to Emailmonday’s national client report.

However, while we’re singing the praises of email marketing, you probably can’t help but envision all of the crappy emails that land in your spam filter each week. Luckily, there are a few things you can take to minimize your emails being flagged as spam, and maximize your open rate. 

One of them is your subject line and this post will focus on email subject line best practices. We’ll tell you everything you need to know from what an appropriate email subject line length is, to how to use language that resonates with your audience. And yes – even how to avoid setting off spam filters. Let’s jump in!

Why should you improve your email subject line?

Assuming you’re not sending cold emails and your campaign is being used on an already established list, your subscribers should recognize your brand in their inbox. However, just because someone subscribed to your list at one point doesn’t necessarily mean they’ll be waiting for your emails with bated breath.

It’s great that you convinced them to sign up for your list, but you’ll also need to convince them to open and read your emails. Your email subject line is your first, and potentially only impression your subscribers have of your email content. These handful of words are what lies between your list clicking the open or delete buttons.

So whether you’re amping up your existing email marketing campaign or just getting ready to launch, make sure each email is using subject line best practices. This will help ensure you maximize the ROI on your email marketing spend, plus make sure all that awesome content you spent time creating gets seen by as many eyes as possible.

Email Subject Line Best Practices

Ideal email subject line length

Generally speaking, the shorter your email subject line, the better. In fact, according to Marketo, four words or fewer in an email subject line tend to perform best.

But we know you can’t always fit your entire message into four words. If you can’t, just keep in mind that your maximum email subject line length shouldn’t exceed 50 characters (you can check it here). That’s because most people regularly check their inbox on mobile devices and you want to make sure your subject line fits on your readers’ screens without getting cut off.

An example of a simple and brief email subject line

Check out this email subject line. It’s four words, simple, and right to the point. This email is from a shoe retailer brand whose list I’m on. They’ve targeted me for this email because I’ve bought a pair of their “Jimmie Flats” before. 

The subject line works because not only does it fit on a mobile device, but it’s simple and brief.  They know I’m a qualified lead and because I’ve purchased from them before, they know the subject line doesn’t need any more detail because I’m already familiar with this product.

So was this email subject line a good choice? Well, it’s sitting opened in my inbox, and not in my trash or spam folders.

Email subject line personalization

Everyone wants to feel special. No one wants to feel like just another number or faceless consumer. That’s why something as quick and simple as personalizing your emails can increase engagement with your list.

You can boost your engagement and open rate simply by including each individual subscriber’s name or other personal details in the email subject line. (And although this post is specifically talking about email subject lines, do keep in mind that it’s a good idea to include similar personalization within the content of the email, as well.)

A personalized email for a birthday greeting

This personalized email subject line is a two-for-one. Not only does it address me by name, but it also mentions my birthday. Was it trying to sell me something? Was it just sending a friendly birthday note? Was it offering me a gift?

Honestly, it didn’t even matter. It addressed me by name and made me feel special on my birthday, so I opened it.

Plus, did you notice it managed to stay within that four-word range?

Using your email subject line to manage reader expectations

It can be fun to use extra creative or eccentric copy for your brand, especially if that’s the type of personality you’ve built for your company. But you might want to think twice about being too outside-the-box with your email subject lines.

As it turns out, straightforward and clear email subject lines out-perform creative ones. Check out the results of this study from Aweber.

Clarity versus creativity test email subject line An average metric of engagement based on a clear subject line

The verdict? People want to know exactly what they’re getting into before they open your emails. And the last thing you want is to confuse your reader and have them expecting different content than what you show them. That’s a quick way to get filtered to spam. So the best way to manage your subscribers’ expectations is to CLEARLY tell them what they will find in your email.

A great example of an email subject line from BabyCenter

Here’s a great example. This email is from a parenting brand that offers tips and development/behavior advice to parents. Its subject line makes it crystal clear what kind of content to expect inside, and the value it will bring me.

Now, all this said, that doesn’t mean you can’t have fun with your copy. Just don’t let your message get lost in translation. 

Choosing the appropriate language for your email subject line

Speaking of choosing the copy for your email subject line, you do want it to resonate with your audience and stay in-line with your brand. This is one of those times when it’s important to understand your customers’ buyer personas.

Try and speak to your subscribers in a way that they would speak. Address pain points or questions you suspect they have. Use language and wording that excites, rather than bores them.

An email subject line from cosmetic brand Morphe

This email subject line from cosmetic brand Morphe absolutely hits the nail on the head.

They’re advertising a collaboration between a popular beauty influencer and their brand. Not only is the messaging crystal clear, but Morphe managed to incorporate Jeffree’s signature catchphrase, “Hey, how are ya?”.

This subject line is a great example of utilizing language that this brand’s audience would relate to, but also establishing clear expectations of the content that’s inside. 

Avoiding a spammy email subject line

Alright, let’s talk about that dreaded four-letter word again: spam. 

No one wants it in their inbox. No one wants their emails ending up in someone’s spam folder. So how can you design your subject lines so that neither algorithms nor subscribers filter your emails there?

Because spam emails tend to be filled with less-than-savory content, and often include scams, the senders try REALLY hard to get people to open them. To do that, they frequently use “Trigger” words to help boost open rates.

Modern email service providers crawl through emails, and subject lines including these trigger words can and do get automatically filtered to spam folders before a person even has a chance to look at them.

While there are certain circumstances you can get away with using trigger words (like if your brand generally has a good reputation, or if you’re sending from a personal email address rather than from a generic @brandname), a good rule of thumb is just to avoid using them altogether  (in both your subject line AND email content) to be safe.

An email received from Wayfair with an exclusive offer

Why is this email subject line spammy? Well it’s clearly trying to sell me something, but all it can tell me is that I have some sort of vague offer. There’s no indication that I’m a returning customer or have ever shopped there before. There’s no mention of any specific items I might be interested in or have looked at. It doesn’t address me by name – indicating that it’s just a mass email.

Everything points to this email being a blanket attempt to sell something to any and every person on its list. It doesn’t provide any real information that would be relevant to anyone. It’s just hoping you’ll open it to learn about whatever “offer” may be inside.

An email with no subject line

Let’s dive a little deeper. This email is especially suspicious because it doesn’t even have an email subject line at all. Not only does that appear spammy, but it alerts my scam flags as well.

An email received with a subject line "Proposal"

One more just to send the point home. First of all, I don’t recognize the sender.

And on top of that, this subject line’s only word is “proposal”. What kind of proposal? Why might I be interested? Why would this even be relevant to me? I don’t know the answer to any of those, so I don’t care.

We did say less is more, but it can’t be so little information that no one knows what you’re talking about.

Those last two emails managed to make their way into my spam folder without ever making it to my inbox. That’s the algorithm at work. 

The right way to use timing in your email subject line

Got a sale or event coming up? Go ahead and include that info right into your subject line if it’s relevant. Remember that you’ll want to avoid spam language so steer clear of wording like, “Act now!”, “Limited time”, “While supplies last”, etc.

But if your big semi-annual sale is coming up this Saturday, that’s important, clear, and honest information you should include in your email’s subject line. Especially if your subscribers need to know that information so they can act on an informed decision.

An email received from Kohl's for weekend offers

Here’s an example of an email subject line educating its subscribers about an upcoming sale without using spammy language. It clearly spells out the deals on the table and indicates that the sale is happening this weekend. But it doesn’t try to unnecessarily push urgency or fear-monger people into opening. 

In fact, Kohls does such a good job on this email subject line that it can get people in the door without them even needing to open and read the rest of the email. They have all the information they need right from the subject. 

Incorporating email preview text

Ok, we’re going to end on a bonus tip since this isn’t technically your email subject line. Still, this is a field you can see before opening an email, so we’re including it on this list because it works in conjunction with your subject line.

Unlike your subject, there’s lots more room for creativity in your preview text. It can answer a question your subject line asks, or be a continuation of your subject line itself. Whatever it is, the content should continue enticing your reader and making it clear to them what the email is about.

Like your email subject line, you’ll still need to be mindful of your allotted space. Generally speaking, you have about 35 – 90 characters to work with in your preview text.

An email received for a flash sale from Victoria's Secret

Victoria’s Secret utilizes all of the space in the email subject line to advertise their flash sale and its potential deals. Then they go one step further by using the preview text to continue talking about more deals, including a freebie.

40% off, plus free shipping, plus a free item with just a $30 purchase is plenty of relevant information that had me clicking through to the email to see how I could qualify. This was a great example of enticing subscribers with every inch of available space they had to use. 

Awesome examples of click-inspiring email subject lines

Now let’s check out a few email subject line examples that use two or more of these tips to get subscribers to open emails.

An email subject line that offers biggest sale

In this example, the company creates a clear subject line regarding the sale and what people can expect to save. Then continues into the preview text with the dates of the sale.

An email subject line reminding you have rewards

The subject line is straight and to the point. Carter’s is reminding me that I have reward points and obviously wants me to spend them. To entice me more, the preview text hits me with information about their 50% off sale.

Email’s subject line with just three words

This one packs a lot in, starting with the email’s subject line of just three words. The subject line also uses language that’s relevant to its subscribers. And although on its own the subject is somewhat vague, it continues right into the preview text to finish the message.

Have you been using email subject line best practices everywhere you can? Got a tried-and-true subject line formula that works every time? Tell us about it! 

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