How to write subject lines that get your sales emails opened

by Steli Efti

The subject line is the most important part of any email, especially if you're sending cold sales emails. If your subject line fails to get the recipient to open the email, everything else you do doesn’t matter.

If an email isn’t opened, it didn’t exist.

Here's how to craft subject lines that compel recipients to open emails.

The most important principle when writing subject lines is this:

Write like a human being

Make it read like it’s written from one person to another, not like it’s written by a marketing department to a prospect. Write like you're just someone writing an email to someone else. 

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Don’t write fancy, formatted emails filled with marketing speak. It’s not a newsletter. You know how many newsletters people get in their inbox every day? It adds up to about a bazillion. It’s the first thing people delete or archive unread when skimming through their inbox. That’s not what you want to happen to your email.

Avoid catchy slogans

I could send you an email with the subject line: " Best New Innovation in CRM in Ages". Many people think a “business email” is supposed to look like this. But if you want to get your emails actually read, avoid it.

Write like what you are: a human being.

Lowercase text

Don’t capitalize every word. Even though it might formally be the (almost) wrong thing to do, writing in lowercase text increases email open rates, probably because when people write an email to someone else, they often don’t capitalize each word.

Subject-line-only emails

Send out emails with only a subject line and no email body text. Using EOM at the end of your subject line also works well. I know a sales team that’s killing it with this technique.

Use their name

A simple and widely used element of successful subject lines is including the recipient’s first name.

You might even want to experiment with ONLY using the first name in the subject line. If I’d get an email in my inbox with the subject line “Steli,” I’d probably open it.

The same thing applies to using the company’s name.


This is a subject line hack that few people use, but using a misspelling can actually increase open rates. Slapdash misspellings that indicate you were typing it hurriedly are a better choice than those that indicate you don’t know how to spell.


  • “Steli, cna we meet today?” (tells the recipient you hurriedly typed it in)

  • “Steli your invited to join us” (tells the recipient you don’t know about punctuation, and the difference between you’re and your)

Ask questions

Questions in subject lines increase open rates. Asking the right questions is an art, and the better you get at it, the more you sell. Use the power of questions in your subject lines as well.

Occasionally we get asked: Will using question marks in email subject lines send your email to the spam folder?

The answer to that question is no. Using question marks excessively is a signal to spam filters that will increase the probability that an email will end up in a spam folder. (The same is true for any other kind of punctuation, whether it's exclamation points or other special characters.)

So a subject line like: "Could this be the best deal ever?????????" has a much lower chance of passing the content analysis part of an spam filter process than one that uses proper punctuation. 

You do however want to ask good questions that are relevant to the recipient of the email. Just asking a question for the sake of asking a question because you think it'll lead to higher open rates will often decrease your open rates. According to a study by Touchstone using question marks resulted in a 8% lower open rate on average.

Your first sentence

Most email inboxes nowadays actually display the first sentence or so of the email body in addition to the subject line. This is another opportunity for you to get your email opened, and you should craft it with your subject line in mind.

Keep your promises

Once you start getting creative with subject lines, it’s easy to get tempted to go too far. Certain subject lines might get you amazing open rates, but you need to look at more than just this one metric. Instead, consider the overall funnel. A lot of cold emailing nowadays is done with the “Re:" subject lines, implying that there’s been a previous conversation.

But your email body should deliver what your subject line promises. If you mislead people to get an email opened, they’ll read your email and delete it. Nothing is gained from that.

Here's an example of a clever subject line tricks prospects into opening the email, but irritates by being misleading: "Your meeting got cancelled".

And one of the most effective attention-getting emails I got was the subject line: “Steli, I’m disappointed.”

I immediately clicked on that email, and then, it went on, basically saying: “I’m disappointed that we weren’t able to connect. What we’re doing is … blah, blah, blah …,” and the email went straight into the pitch.

That email was like a guy running a marathon, sprinting the first three miles, being ahead of everyone else … and then collapsing and never making it to the finish line. It was the first email that I opened in my inbox, but once I saw that the subject line was just a clever trick and the sender wasn’t really disappointed, I didn’t bother responding.

2 bonus tips for effective cold emails

Now that we've covered these common email subject line best practices, let's look at two more tips to help you in your cold email efforts.


If you’re doing cold emailing professionally, you probably know about common email subject line best practices. Statistics show that the best time to send emails is around 8 or 9 a.m. (local time of the recipient) on Tuesdays and Thursdays.

That’s exactly why you should experiment with doing something else. So many people are following these best practices that by Tuesday at 9:00 am, prospects' inboxes are flooded with dozens of cold emails and newsletters.

Try the contrarian approach and send out emails at odd times, such as weekends, 5:30 a.m. or super-late. Experiment to see if odd timing can increase your response rates.

"Sent from my iPhone"

Just add this little line underneath your signature. We used this a lot when we were running ElasticSales, and consistently saw a large increase in response rates. Even with autoresponder emails and drip campaigns, consider using this. It feels a bit deceptive, but it’s very effective for most audiences.

Want more tips and templates?

cold email hacks report