Subject lines for sales emails: do’s and don’ts (with examples)

May 27, 2021

Read. 6 min.

Subject Lines for Sales Emails | Do’s and Don’ts

Subject lines in your sales emails are often your only chance to make a first impression on a potential customer. Don’t let it go to waste. Here are some features of great subject lines, and some subject line tactics to avoid in your sales emails.

There’s a reason emails have stuck around, despite being unpopular with consumers -- they work!

Only about 24% of sales emails get opened, according to Gartner. Those emails have a higher chance of reaching and converting prospects, though!

Research from HubSpot found that 8 in 10 prospects want to talk to sales reps over email. So, even though prospects are opening fewer emails, emails are their preferred mode of communication.

How do you make sure your prospects are opening your sales emails? With an amazing subject line that addresses their pain points and shows you did your research.

Read on to learn more about what makes a great sales email subject line.

Why are subject lines so important for sales reps?

Your subject line is an opportunity to win over your prospect and introduce yourself and your product.

The average person receives scores of emails each day. Most never get opened, and the ones that do are only read for a little more than 8 seconds.

Graph showing share of emails that got glanced, skimmed, or read from 2011-2018


A well-crafted subject line helps your email break through your prospect’s inbox. It inspires a lead to click and learn more, without seeming spammy or fake.

Here are the 3 features of great sales subject lines.

Top 3 features of great sales subject lines

A great subject line for a sales email is similar to a great subject line for a marketing email. To maximize your chances of an open or click, your subject line should be:

  1. Short: Keep your subject line to 3-4 words maximum. Remember, your recipient’s only looking at this for a few seconds. Pick the 3-4 words that will leave the biggest impression.
  2. Customized: Most savvy internet users are aware that businesses use data to personalize their outreach. Customize your subject line in a way that shows you did your research, not just “Hey, [First name]."
  3. Human: Just because your outreach is automated doesn’t mean you can’t sound like a human in your subject line. Try writing your subject line all lowercase, or “accidentally” including a typo to boost your open rates.

3 subject line "don'ts" for sales reps

Now that we’ve covered what should be included in your sales subject lines, here are some sales subject line tactics you should avoid:

1. Don't include your company name

It might seem like a no-brainer to include your name or your company’s name when introducing yourself in a subject line.

Including your company name in your subject line, however, ends up removing focus from the customer’s pain points.

Don't use your company name in subject lines

2. Don't make the format too "perfect"

A perfectly polished subject line screams “this is a sales email” to potential customers.

Avoid taking up valuable subject line real estate with tricks like “//” or “<>.” Remember, prospects want to know that you’re a human being who understands their needs!

Don't make subject lines too "perfect"

3. Don't use personalization if it looks fake

Personalization can be a good thing sometimes, but when done poorly, it can drive your prospect to ignore or delete your carefully crafted email.

Most people are aware of the powers of modern email clients to personalize content based on data. If you’re going to include a name, make sure your subject line and preheader text have enough personalization to match.

don't use personalization if it looks fake

5 tips for great sales email subject lines

Now that you know what not to send to your leads, here are 5 tips you can follow to craft winning subject lines in your sales emails:

1. Research your prospects

Building an outreach list already takes a lot of research, but to craft a winning subject line, you need to take your research to the next level.

Finding your prospect’s name, title, company, and email address should be just the beginning. 

Research your prospect’s company: its business model, its pain points, and other employees that could be part of the purchasing team. Creating this basic persona will help you choose the words in your subject line wisely, and allow you to focus on the rest of the email.

2. Be human

Make sure your prospect can see you're human, even if you are reaching out through an automated system.

Use tokens and other marketing automation tools sparingly, and opt for other ways to add a personal, human touch instead.

Typos and lower-case writing can help your prospects see that your outreach is coming from a person, rather than a company or an email sequence.

3. Test, test, test

When an email is one of your primary forms of outreach, you should take every opportunity to experiment with different subject line techniques.

Some of the subject line elements you can test include:

  • Number of words
  • Title case and sentence case (e.g. “Book a Call” vs. “book a call”)
  • Typos
  • Personalization

Treat your email subject lines as opportunities to experiment with your outreach and identify trends that will lead you to more email opens.

4. Avoid spam traps

Email spam filters are more sophisticated than ever, and cold outreach always runs the risk of being flagged as spam by email clients.

Certain subject line elements make your email a target for spam filters. Words like “free” or “discount,” as well as all-caps spelling, can cause your sales email to go directly to your prospect’s spam folder.

According to HubSpot, some of the top types of spam trigger words for emails are:

  • Financial: anything mentioning cash, credit, bargains, or free
  • Business-related: terms such as “increase sales” and “explode your business” can come across as spammy
  • Sense of urgency: “limited time” and “offer expires” are likely to trigger a spam filter

Make sure your email lands in front of your prospect and not in their spam folder.

5. Be original

Your subject line is your first (and maybe your only) opportunity to really stand out from the crowd in your prospect’s inbox. You don’t want to be just like everyone else.

Find ways to let your personality shine through in your subject line and preheader text. Think about sales emails you’ve seen come through your inbox and brainstorm ways to improve them.

Selling is a human process, so letting your individual personality and company brand shine through can help your prospects identify you as worthy of their attention and trust.

Follow these techniques for winning sales subject lines

Email isn’t dead, and crafting a winning email subject line is still worth your time as a sales rep. Conveying your company’s value proposition in a few short words can be a challenge, though.

Your subject line is a chance to show your prospect that there’s a human being on the other side of the email. Use personalization and automation wisely and keep your subject lines short.

Finally, don’t be afraid to test what types of subject lines work for different audiences. Once you get past that initial email, the true engagement can begin.

Start wowing buyers and hitting quotas now