Cold Email Subject Lines: 15 Best Practices + 25 Examples

You just met me.

I’m giving you three seconds – no, one second – to convince me that you’re worth listening to. If you don’t, I’m walking away and you’ll never have a chance to talk to me again.

What do you say to get me to keep listening?

In some ways, this analogy mirrors the acrobatics you’ll need to pull off to write a convincing cold email subject line.

This is someone you’ve never met before (usually). They don’t want to hear from you. They have a cluttered inbox already. And they don’t have time for your sales pitch.

So realistically, you’ve got just a few words to convince this total stranger that they should, in fact, open your email.

In other words, the subject line of your cold email.

And in this guide, I’ll teach you everything I know about how to write a great one.

By the way, we offer a done-for-you B2B lead-gen outreach service — so rather than worrying about doing all this email stuff on your own, we can do it for you! Interested? Grab a time from my calendar and let’s chat!

Are Cold Email Subject Lines Really That Important?

I’ve written about the importance of subject lines before.

In many ways, the subject line of your cold email is the most important part to get right. Most people look at the subject line before opening any email, and if it doesn’t seem worth reading, they simply delete it.

Screw this up, and your prospect is simply going to move on.

The stakes are even higher because this is a cold email. This person doesn’t know you or your company. They haven’t heard your amazing jokes and haven’t seen your astounding smile. So they don’t know that you’re worth talking to yet.

The subject line is your only real shot at convincing them.

Cold Email Subject Line Best Practices

What are the best practices for writing a cold email subject line?

1. Know your audience.

There are some solid, generic subject lines. But I encourage you not to use them.

Why?

Because you’ll be much more successful if you write a unique subject line that’s perfectly suited to your target audience. To do that well, you’ll need to know your audience first – which is, incidentally, why this is the first best practice on the list.

Get to know your target demographics inside and out. And if you have multiple audiences, segment them. Your cold email subject lines should fit them like a glove.

2. Keep it short.

You’re a busy person. You know what it’s like to open an inbox and see 100 unread messages. It sucks.

Make your recipient’s life easy and keep the subject line as trim as possible. A few words is plenty. Maybe you can get away with a full sentence.

But you definitely need to cut the fat and only include words that are necessary to get attention or prove your point.

3. Personalize it.

Though not all your cold email subject lines will be able to be personalized, you should include personalization when possible.

Including the person’s first name or the name of the company they work for can instantly make it seem more important.

4. Imply value.

Speaking of importance, you should try to imply that what you have to offer is valuable, in some way.

For example, you could mention that you have a tip that saves people an average of $10,000 per year. Or you could allude to the whitepaper you recently published.

5. Imply urgency and stoke FOMO.

People are lazy. We procrastinate constantly.

That’s why even an okay subject line can keep your email unread and/or deleted.

If you want to increase your open rate, you need to imply some degree of urgency. Make it important for the recipient to open the email soon – preferably within a day or two.

You can also capitalize on FOMO this way – the fear of missing out. Make it seem like other people are already benefitting from your email.

6. Be wary of spam filters.

Before sending any cold email, you should know how spam filters work – at least a little bit.

If your subject line contains specific trigger words that make it seem like spam, it might never reach its final destination.

Avoid spammy subject lines like “FREE BOAT GIVEAWAY!!!!” or “LOSE 20 POUNDS BY TOMORROW!!!!!”

7. Tease something.

If your subject line contains all the valuable information, why would people bother to open the email?

It’s important to tease something in your subject. Imply that there’s something more to learn or something more to gain by opening the message.

Even something clickbaity like “You’ll never guess what [brand] is doing now” can work because of this principle.

8. Be confident, but realistic.

Be assertive and confident in your messaging. Use your subject line to say something with authority.

A subject line like, “I can boost your sales by 20 percent” is much better than “I might be able to help you?”

Just try not to go overboard. If you make a promise that’s too bold or too salesy, it’s going to turn people off (even if it’s true).

9. Be sincere (and show your brand’s personality).

It’s also helpful to be sincere and try to show off your brand’s personality. When it comes to cold email tactics, too many brands adopt a stale, generic “professional” persona.

But this doesn’t help you stand out. Instead, show off what makes your brand distinctive.

10. Evoke an emotional response.

People are much more likely to open an email if they feel some kind of emotion when seeing your subject line for the first time – even if that emotion is somewhat negative.

For example, you can tell your recipients something surprising, or some unique good news. You could also make a controversial claim or report on some bad news.

Obviously, though, you need to be careful if you’re stoking negative emotions in your target audience.

11. Make it easy.

Again, people are busy. If you want to maximize your chances of getting an open, make your ask ridiculously easy – and include it in the subject line.

Leading with something like, “do you have 5 minutes?” is going to get better results than, “can we meet later today?” because the latter is ambiguous – and could therefore be super time consuming.

Vague, but fast-paced subject lines, like “quick question” also work.

12. Recall a previous interaction.

“Cold” emails imply that you’re total strangers. But you might send a cold email to someone you’ve met or seen once before. If this is the case, mention the previous interaction.

Something like “how have you been since [event]” can work well.

13. Offer metrics or stats.

People like to see objective evidence. It assures them that the information is accurate and makes you seem like more of an authority.

That’s why including numbers, facts, and statistics in your subject line can instantly boost your open rate. Include one to round out an already strong subject.

14. Remember the snippet.

Here’s a subject line tip that’s not about subject lines. Stick with me on this.

In most email clients, you’ll see a “snippet” of the email body next to the subject line before you open it. It’s almost like an extension of the subject line – something your recipients see before opening, and something that will form their first impressions of your message.

Because of this, you should treat the first line of your email body with the same respect and reverence that you do the subject line. Make these first few words count!

15. A/B test and adjust.

Even the best subject line writers struggle. That’s because thousands of variables can impact how they work, and good on-paper strategies don’t always work practically.

What’s the solution? Experiment.

Try out new subject lines, measure your results, and learn from your past experience.

Cold Email Subject Line Examples

Now let’s put those best practices into practice, as best we can.

Below are some of my favorite examples of effective cold email subject lines. Feel free to use them directly, but they’ll be even more effective if you tinker with them and adjust them to better suit your personality (remember best practice #9!).

1. Introducing myself

This is my go-to cold email subject line. It just works! It’s short, simple, and people want to know who is making an introduction.

2. quick question

This is one of my favorite cold email subject lines because it seems like it’s coming from a real person and not some super fine-tuned marketer or salesperson. The lower-case q on “quick” is purposeful – it just looks more human. And that gets this email opened.

3. reaching out

Same here – but this may be a bit too vague for some people.

4. [name], what’s the biggest challenge in SEO?

This personalized approach opens with a question, piquing curiosity and forming an instant bond.

5. [name], want to increase [company]’s cold email ROI by 25 percent?

Look at that sweet number. Again, this is personalized.

6. How 11 startups increased productivity by 20 percent.

Love that social proof – just be prepared to back it up in the body of your message.

7. Congratulations on the [award/event]!

Know about something cool that happened to this person, like a promotion or a recent published book? Mention it!

8. [Connection] referred me!

Though we’re not exactly “cold” in this scenario, if you got a referral to connect with someone, mention them!

9. You’re invited

Have an upcoming event or webinar? This is an awesome way to tease it.

10. coffee?

Another presumptive invite, this is often more appealing than a video call or live demo. Consider offering lunch or dinner instead.

11. Are you going?

Is there a big industry event coming up? Allude to it like this.

12. How can I help?

That’s a heavy question, but one that will spark curiosity in most.

13. Great meeting you

Again, we’re more in “warm” email territory here, but if you’ve connected with this person in any way, it’s worth bringing up.

14. Next steps

Imagine getting this email without remembering the first steps you took – you’d want to know more, right?

15. Sorry we missed you!

This makes for a good follow-up email subject line, but can also work by itself.

16. Interested in [product]? Read this first.

Mention your competitor’s product here to hook them.

17. 10 insights to change how you see [industry].

A strong number leads this subject line, which in turn leads a prospect to want to know more.

18. Get rid of [problem] in 10 minutes.

The better you know your audience, the better this will work.

19. Your competitors are achieving [achievement]. Are you?

Use research to back up your claims.

20. A marketer and a salesperson walk into a bar.

Humor is often effective (for the right audience), so consider leading with something funny, or the promise of something funny, like this.

21. Want to hear something embarrassing?

Don’t talk about the time you asked Gertrude to the prom. Talk about lost productivity or something related to your product/industry.

22. You’ll never see [product] the same way again.

Ooo, this one’s spicy. It has a powerful hook to draw people in, but if you can’t back it up, it may be taken poorly.

23. Our latest whitepaper, free for a limited time.

The clock is ticking. Make it count!

24. The customer is not always right.

Sometimes, boldly polarizing statements or opinions like this can stand out in an otherwise cluttered inbox.

25. Last day to lock in pricing.

Another great way to imply urgency – and it’s even more effective if you have a valuable offer in the body of your message.

Great cold email subject lines have the power to considerably improve your bottom-line email sales figures.

But they’re not the only thing you need.

You also need a fast average response time, concise messaging, emails that actually land in your recipient’s inboxes (see my article on email warmup tools for help with that), and a consistent strategy for reaching the right people.

Oof. How are you going to do that?

I don’t have the solution to every problem, but I do have an awesome tool that can help.

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It’s got all the information you need to dissect – and eventually improve – your email sales strategy.

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