I judge every email subject line that makes its way into my inbox. I’m not exaggerating when I say that the subject line is the sole factor I use to decide whether the content of the email will be interesting to me.

Maybe I’m extra critical of email subject lines because I’m a marketing writer. I know how much brainstorming goes into coming up with catchy subject lines that will entice a subscriber to open the email.

In fact, according to our 2024 State of Marketing Report, 62% of email marketing teams take two or more weeks to create an email.

With over 347 billion emails sent around the world per day, the subject line is your only chance to stand out in a crowded inbox. Read on for some tried-and-true tips to help personalize your subject lines and boost email engagement.

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What makes a good email subject line?

According to our 2024 State of Marketing Report, 41% of email marketers consider email marketing their most effective channel. The first step in making your emails more effective? Use a good email subject line.

There’s a lot weighing on your email subject line. Not only is it the first thing subscribers see in their inboxes, but it also helps them decide if they want to open your email or not.

A good email subject line aims to pique your subscribers’ interest so they’ll open the email and ultimately click through to whatever you’re promoting within it.

Hyper-personalization is key to email marketing in 2024, and subject lines are a major contributing factor. Plus, with the innovation of AI tools, they can be used to collect and organize subscribers’ personal data and behavior analytics.

And when you have this data, there are endless opportunities to craft subject lines that are not only engaging but highly personal.

Our report found that AI-powered personalization in marketing can increase ROI by up to 70%. How? You can grab subscribers’ attention by offering something you know what they want, such as entertainment, information, or a discount.

Before we get to our tips, let’s go over some fundamentals of what makes a great subject line.

1. Urgency

Creating a sense of urgency is an efficient way to get people to take action. Subject lines that use words like “urgent,” “breaking,” “important,” or “alert” can communicate urgency.

By communicating a known start and end date for a special sale or promotion, viewers scrolling through their inbox will click to see what they can get in that window of time.

This is best done in a series of emails counting down the window of opportunity — as long as you don’t flood their inbox, which comes off as spammy.

You can also create urgency for webinars or content by making them ungated for a set amount of time and then giving your viewers codes or temporary access to the content.

2. Curiosity

Subject lines sometimes work because they can send the message, “You will benefit from opening this email.”

But other times, it‘s good to maintain some mystery — especially if it piques the recipient’s natural curiosity and interest. I know from personal experience that curiosity often drives my decision to open emails.

Because they require opening the email to get more information, curiosity-driven subject lines can result in a higher open rate. But make sure the subject line, while enigmatic, still aligns with your brand.

Too obscure, and it could end up being seen as spam.

3. Offers

Here’s where the benefit of opening a given email comes in. At the end of the day, people love new things and experiences, especially when they’re free or at least discounted. Open with that by including it in your subject line.

Personally, I‘m much more inclined to open my daily newsletters when there’s an offer or allusion for “free stuff” directly mentioned in my inbox.

4. Personalization

No two email subscribers are the same. Sometimes, that means the emails you send to them shouldn‘t be, either. At this point, marketers have never had more ways to learn about their subscribers’ preferences, jobs, or general (dis)likes.

As we mentioned above, there are plenty of AI tools available to help you collect and organize personal and behavioral data that can be used to improve your email personalization.

5. Relevance and Timeliness

When I subscribe to an email list, it’s typically because I want to be kept informed or learn more about a given topic (more on that later).

Similar to piquing your audience’s curiosity, crafting email subject lines that incorporate trending topics or timely headlines can help you establish your brand as an authority within your industry — and can compel people to click to read.

6. Name Recognition

Let’s face it: We all admire a famous person or two. At the very least, we’d be compelled to open an email with certain celebrities’ names attached.

When you understand your audience’s preferences, you can pique their interest by including the names of these recognizable individuals in your content — and mentioning them in your email subject lines.

But take heed: This tactic only works when it aligns with your brand, product, or service. So keep it relevant rather than just throwing out a name for the sake of recognition.

7. Cool Stories

At the risk of sounding like a broken record, here’s another place where curiosity comes into play.

By front-loading your email subject line with a compelling allusion to a story — that can only be read if opened or clicked — your audience is likely to become intrigued and want to learn more.

Pro tip: Make sure the story is relevant to your brand. Otherwise, it can confuse your readers and prevent them from opening the email.

8. Length

While shorter is usually better, there may be times when you have to use more characters to get your message across. Just be sure that it fits within the character limitations of the average display.

For example, the Mail app on iPhones displays up to 78 characters in the subject line area. And when you consider how many people read emails on their phones, your subject line length is important to think about.

Don’t be afraid to A/B test how long your ideal subject line should be. Martech Zone offers a helpful tool that lets you see how your subject line appears in different email apps.

Now that you know the fundamentals, let’s dive into email subject line best practices.

 

Email Subject Line Best Practices

1. Learn from successful email subject line examples.

I often look to examples for inspiration whenever I’m brainstorming or stuck on what to use for an email subject line.

Seeing clever use of wordplay or emojis on one of our favorite newsletters can help us think of new ways to approach our subject line.

To help you do the same, we‘ve compiled a list of 100 email subject lines from real businesses. We hope you’ll be just as inspired.

Download the Free Email Subject Lines Examples Guide

2. Get to the point.

As I mentioned above, email subject lines will get cut off if they’re too long, particularly on mobile devices.

Since 55% of emails are opened on mobile, we recommend using subject lines with fewer than 50 characters to ensure that the people scanning your emails read the entire message.

If you‘re struggling to keep your subject lines short, think about which words matter less and where you can remove a frivolous detail.

For example, if you’re sending an order confirmation, doesn’t “Your order is being processed” look better than “Order #9435893458358 is being processed”?

The same goes for your regular emails: Don’t waste your time including the word “update” or “newsletter” in the subject. Some studies suggest these words can decrease your open rate.

This language tells readers the email is one in a series, and therefore, they can catch the next one.

3. Use a familiar sender name.

That name recognition we mentioned earlier doesn’t just apply to the famous — it applies to the familiar.

When setting your sender name, be as human as possible. Olivia@yourcompany.com is both inviting and unintimidating to people when they open their inboxes.

If you‘ve already met your recipients from a previous conversation, use your own name as the sender’s address — even if the email is technically coming from the company as a whole.

The best impression you can make on your customers is that they’re working with you, the individual.

Ultimately, people are busy. They simply don‘t bother if you don’t sound like someone who would make for an easy (or at least friendly) conversation.

4. Avoid the ‘no-reply’ sender name.

Thanks to the amount of spam people get, most people hesitate to open emails from unfamiliar senders. Even fewer people enjoy talking to a robot. Think about when you call a company and can’t get a hold of an actual person.

It’s frustrating, right? This is the same for email.

Never use “noreply@company.com.” Not only does it look less personable, but it also stops people from adding your email to their address book.

Instead, avoid using a generic email address and send the email from a real person.

(HubSpot customers: Learn how to personalize the “From” name and email address here.)

5. Use personalization tokens.

Remember the personalization we mentioned earlier? Using personalization tokens — like name or location — in the subject line adds a feeling of rapport, especially when it’s a name.

Everyone loves the sound of their own name. Plus, it increases click-through rate: Research has shown that emails with the recipient’s first name in their subject line had higher click-through rates than emails that did not.

The example below is an email I received from the personal finance company Credit Karma. The email subject line grabs my attention by using my first name and sharing a promising offer to lower my car insurance payment.

The company is able to personalize this email using the data it has about my car insurance payment, demographics, and location.

Another personalization tactic that works is to tailor subject lines to the recipient‘s location — things like lists of their respective cities’ best outdoor bars and restaurants.

Little personalized touches show that you know more about your recipient than just their email address.

However, if you can‘t (or don’t want to) use personalization tokens in the subject line, use “you” or “your,” so it still sounds like you’re addressing them directly.

Just don’t go overboard with the personalization here. That can be a little creepy.

6. Segment your lists.

While email blasts that go out to your entire list might be relevant and helpful to some people, they won’t be to others — causing confusion and frustration.

Why is this restaurant sending me a list of the best local steakhouses when I’m a vegetarian? Why is this company sending me case studies when I just signed up for its email list yesterday?

This is where segmentation comes in. When you organize your email list using personalization and preferences, you increase your subscribers’ desire to open your email.

Gartner found that 53% of consumers like emails that share local or regional events and offers.

Personalize the experience using information from your customers‘ actions — from which forms they’ve filled out to which industries they’re in and what their personal preferences are.

In email marketing, you can personalize your recipients’ experience using a little thing called list segmentation.

7. Use AI to get personal.

AI tools can be used to personalize both subject lines and email content.

Implementing AI in your subject lines may look like adaptive testing.

Adaptive testing identifies variations in traffic/open rates and adjusts the traffic automatically so that better-performing variations are shown more and poorer-performing variations are shown less.

Having a hard time coming up with variations? AI is good for that, too. A generative AI tool, like HubSpot’s Campaign Assistant or AI email writer, can come up with dozens of ideas in a single click.

Check out this article on how you can use AI to optimize your content.

8. Don’t make false promises.

Your email subject line promises your reader what you will deliver in your message. Make sure you make good on that commitment, and don’t try to get your email opened by making false promises.

This will irk your audience, and they’ll learn not to trust your subject lines, resulting in a lower open rate and a higher unsubscribe rate.

9. Do tell them what’s inside.

Speaking of making promises, if your visitor has downloaded an offer and you‘re delivering it via email, it’s a great idea to use a subject line that says something like, “Your new ebook inside!” or, “Your guide awaits!”

This works better than a simple “thank you” in the subject line because it makes it clear that something is waiting inside the email.

10. Time it right.

Sending an email at the right time with the right subject line can make a huge difference in open and click-through rates.

A prime example? When food publication Eater sent an email at 6:45 P.M. on a Wednesday evening that said, “Where to Drink Beer Right Now” — it was just in time for happy hour. Nailed it. Or, in the example above, IRC Recipes sent an email during the day that asked, “Need something tasty for lunch?”

The day of the week matters as well. Tuesdays have the highest email open rates (nearly 27%), compared to Sundays, which have the lowest open rates (4%).

Another favorite example is a classic email from Warby Parker with the subject line, “Uh-oh, your prescription is expiring.” It was sent two weeks before the recipient needed to renew his prescription.

By sending an email at the right time, Warby Parker increased the chances of their email getting opened — and included a relevant call-to-action about getting a glasses upgrade, too.

11. Use concise language.

Keep in mind that people scan their inboxes very quickly — so the clearer and more concise your subject line is, the better.

It‘s usually a lot better to be concise than it is to use complex and flowery language — unless you’re going for an elusive subject tone to entice your recipients.

When you’re going for a concise subject line, think about how your email will benefit your recipients.

You’ll want to make that benefit very clear. For example, “Increase your open rates by 50% today” is more appealing than ”How to increase open rates.”

If your subject line needs to be longer, just make sure it is relevant and worth it.

Research from Gartner found that 13% of people unsubscribe from emails that are too long. And if you can’t be concise in your subject line, subscribers won’t feel confident you can be succinct in the rest of the email.

12. Start with action-oriented verbs.

Subject lines are similar to calls-to-action in that you want the language to inspire people to click.

Subject lines that begin with action verbs tend to be a lot more enticing, and your emails could be drastically more clickable by adding a vibrant verb at the beginning.

Actionable subject lines will inspire people to click on your email by instilling urgency and excitement.

For example, in an email inviting people to a hockey legend dinner, the email subject line might read, “Dine with Bruins legend Bobby Orr,” rather than a more generic “Local Boston Sports Legend Meal.”

The former email uses “dine” to help the reader envision themselves at the table.

13. Make people feel special.

The psychology of exclusivity is a powerful thing. When people feel like they’re on the inside, it gives them a sense of belonging, which builds loyalty and compels them to convert on your emails.

The right phrasing can make your recipients feel special — and the effect can be magical. A few ideas for phrasing include:

• “For our beloved customers only…”
• “An exclusive offer for you…”
• “My gift to you…”
• “You’re invited!”
• “Private invite…”

14. Create a sense of importance.

For many of us, there’s a phrase reminiscent of classic infomercials: “Act now!”

While we wouldn’t encourage using that exact language in your content, we agree that communicating urgency and scarcity in an email subject line can help compel readers to click (or act) when phrased creatively and strategically.

Pro tip: You don’t want to be known as “the brand that cried wolf,” so use these subject lines sparingly, and try to limit them to when the occasion genuinely calls for immediate action.

15. Use numbers.

Many businesses send emails with vague statements in their subject lines.

That’s why using data and numbers is a great way to get your emails noticed, demonstrate a clear and straightforward message about your offer, and set the right expectations.

I’ve found that, like blog titles, using numbers in your subject line is an effective email marketing best practice.

You might use numbers to refer to the title of your listicle, the page length of an offer, a specific discount, or the numerical benefit of a particular resource you’re providing — like “Join more than 750 others at this event!”

16. Pose a compelling question.

Asking a question in your subject line can also draw readers in — especially if you‘re asking a question you know is relevant to your recipients’ buyer persona. This is just one way to pique that curiosity we mentioned earlier.

For example, you might try the following: “Are you making these SEO mistakes?” or “Do you know what your website is doing wrong?”

Zillow once sent an email with the subject line, “What Can You Afford?” that linked to a website showing apartments for rent.

A subject line like this is both encouraging and a touch competitive: While it gives hope that there are apartments out there that’ll fit within your budget, it also pits your cash against what the market offers.

Another example comes from DocuSign. Late in the lead nurturing process, it sent an email with the subject line, “What are your customers saying?”

The body of the email contained case studies meant to help the recipient move closer to actually purchasing DocuSign.

This was a smart move: Folks further down the funnel are likely more receptive to customer testimonials.

17. Don’t be afraid to get punny.

Most people love a good pun. It’s a great way to delight your recipients and spice up your emails. Some of the best punny email subject lines come from JetBlue, with subject lines like “Land wander-ful low fares now!”

Quirky — a community-led invention platform — worded one of its email subject lines like this: “Abra-cord-abra! Yeah, we said it.”

That second part is conversational and self-referential — exactly what most people would say after making a cheesy joke in real life.

Pro tip: If you‘re the least bit punny, think about small ways to slip them into your emails when appropriate. Just don’t overdo it. And remember the rule: When in doubt, ask a coworker.

18. DON’T USE ALL CAPS or overuse exclamation points!!!

A subject line that says, “OPEN NOW AND RECEIVE A FREE TRIAL” or, “50% off coupon today only!!!!!!!!” isn‘t going to get your email opened. If anything, it’ll probably get your email ignored. Or worse, marked as spam.

Why? People don’t like to be yelled at, and using all caps and/or a lot of exclamation points can rub people the wrong way.

Not only are these tactics disruptive, but they look spammy.

So, instead of using disruptive tactics like these to stand out in people’s inboxes, try personalizing your emails, establishing relevance, and using catchy and delightful language to show excitement.

19. Don’t include a question and exclamation in the same subject line.

Here‘s a subject line that can automatically wind up in a recipient’s spam folder: “Want a solution fast? Act now!”

The fast solution isn‘t the problem in the example above. It’s also not “act now” — although those are known email marketing spam words. It’s both phrases together.

This is a classic email saboteur, and it comes in many forms. All you need is to ask and yell at the same time.

Web servers often flag emails as spam if they contain both a question mark and an exclamation mark in the subject line. The example above is a common one. Is that a good solution? Don’t do that!

Not only is this format overdone, but it alienates your audience. Open-ended questions show ignorance; any good marketer knows their leads better than that.

20. Use engaging preview text.

While preview text isn’t technically part of your subject line, it appears right near the subject line and certainly deserves your attention.

Preview text gives recipients a peek at the content inside your email, which clients like the iPhone Mail app, Gmail, and Outlook will display alongside the subject line.

(The exact amount of text shown depends on the email client and user settings.)

When you don‘t set the preview text yourself, the email client automatically pulls it from the body of your email. Depending on your email content, this can look messy, and it’s also a wasted opportunity to engage your audience.

(HubSpot customers: Click here to learn how to set the preview text of your emails.)

21. A/B test your subject lines.

Although these tips and best practices are a great place to start, what works best for some companies may not work as well for others. It‘s all about figuring out what works best for your specific audience. That’s where A/B testing comes in.

While it can be tempting to use your intuition to predict what subject line language will make people click on your emails, you should always A/B test your highest-stakes subject lines and tweak the wording according to your results.

What works best for your audience: Long or short subject lines? Including numbers or not including numbers? Questions or statements? (HubSpot customers: Learn how to A/B test emails in HubSpot here.)

22. Reach out again.

A common problem in email marketing is sometimes, despite your best efforts, readers simply don’t open your emails. However, current stats demonstrate that marketers are missing out on further engagement.

When retargeting, make this known in your subject line with something like “Oops, looks like you missed this!” or “Don’t forget to sign up for this Friday’s webinar” or whatever you’d like a missed target to acknowledge.

Now that we’ve gone over the best practices, let’s review the steps to creating effective email subject lines.

 

How to Write Good Email Subject Lines

Step 1: Identify the purpose of the email.

Why is the email being sent, and how does that inform the subject line?

Identify the true purpose or intention of the email and use that as the foundation to build upon when brainstorming your subject line idea.

Step 2: Determine the call to action.

What will make the user click on the email? A discount? Something free? Important information? What is enticing enough to make them want to see or learn more about your offer?

Having a call to action with an incentive yet to be seen is tempting.

Step 3: Make it relevant.

Why should your reader open this particular email? Consider making your email time-sensitive or unique with a date or time-limited promotion.

Step 4: Draft multiple subject lines.

Write similar subject lines that use varying words and tones. You want to have a few ideas to choose from so you’re not stuck stewing over the same sentence for too long.

Step 5: Get feedback.

Have colleagues review the subject lines and give their feedback on which they prefer. Having a second opinion can help you see it from a different perspective.

Step 6: Test your subject line.

As mentioned earlier, perform an A/B test to see which subject line performs best.

After you’ve conducted the test, take the most effective email subject line and use it in your upcoming email marketing campaign.

Now that we’ve covered the steps to creating a good subject line, let’s examine some effective examples.

 

Examples of Catchy Email Subject Lines

To give you some added inspiration, here’s a quick list of the most intriguing subject lines I’ve seen in my inbox recently.

Doen: Ending Soon | Favorites Up To 70% Off ⏳

This email subject line from clothing brand Doen communicates a sense of urgency from a time-bound sale. Coupled with a relevant emoji, these two tricks create an email subject line that would stand out from the rest of your inbox.

Why I like this: I immediately opened this email when I saw it. Not only did it lead with urgency by letting me know the sale was ending soon, but it also reminded me of the major discount I could be missing out on if I didn’t shop now.

Hunter.io: Email outreach vs. GDPR

This example from Hunter is simple but effective. Hunter is a tool you can use to find and verify professional emails, so it makes sense to share guides on a topic that most of its subscribers would be interested in.

People who use the tool to find contacts and send cold emails will undoubtedly want to ensure they’re compliant.

Why I like this: This email grabbed my attention because it was straightforward and clear that it would be informative. I made a note to come back to this email so I could read the included article later.

Clearscope: Your final reminder: Q&A panel invitation

Clearscope, an SEO tool, sent this email as a follow-up reminder about an upcoming webinar it was hosting.

With the number of emails people get these days, it’s never a bad idea to send follow-ups and reminders, especially for events that people need to sign up for.

Why I like this: When I saw this email subject line in my inbox, it felt like something I received from a colleague instead of from a company. The email led with a sense of urgency, but it also included the word “invitation,” which served as a reminder to RSVP to the upcoming event.

For Your Party: Is This The Perfect Bachelorette Theme?

Back when I was wedding planning, I subscribed to emails from For Your Party, a custom party supply company.

This email subject line from the brand uses a question to generate interest with its subscribers. And, as we mentioned earlier, posing a question is a smart way to drive open rates.

Why I like this: While I’m not in planning mode anymore, seeing an email subject line like this if I were planning a bachelorette would immediately pique my curiosity.

Bloom Nutrition: Prime Day prices are BACK! 🎉

While we cautioned against CAPS lettering earlier, it doesn’t overwhelm this email subject line.

Bloom Nutrition lets its subscribers know that its discounted Amazon Prime Day prices are back for one more day, so the emphasis on BACK — followed up by a celebratory emoji — is warranted.

Why I like this: This email landed in my inbox the day after Amazon’s Prime Day (and all of its major discounts) ended. If you were like me and missed out on a sale or promotion, seeing this email would bring a sense of excitement and encourage you to add to your cart immediately.

Monos: Escape to the Baja’s brilliant shores

Luggage brand Monos creates a vision for its subscribers with this descriptive email subject line.

If you’re like me, you immediately envision yourself on the beach after reading this subject line, which is exactly what a travel brand would hope to achieve.

What I like: The best part about this email? It was sent in January. The timeliness makes the email even more enticing, as most subscribers are probably dealing with the frigid winter weather while dreaming about the warm beach.

 

Catch More Clicks With Catchy Subject Lines

At the end of the day, if your emails aren‘t getting opened, they’re not getting seen.

Your email subject line is the gateway to the rest of your email, so it needs to capture your subscribers’ attention. Experiment with different formats, styles, and lengths to figure out what they’re most drawn to.

In my experience, shorter email subject lines tend to get my attention as I’m scanning. But I’ll also open a long email subject line if it’s from a brand that I enjoy. My point is, every email is different which means it’s worth it to experiment.

By using some of our tips, we hope you can come up with creative and engaging subject lines of your own. You already have great content to share — now, prove it in your subject line.

Editor’s note: This post was originally published in July 2016 and has been updated for comprehensiveness.