Your opening line is always important. Whether you are performing a comedy sketch, making a political speech, picking up a date, or crafting a great email, you need a great opener. But how do you do this? What rules do you follow?

After compiling some research from companies like Litmus, Sendgrid, Return Path, and some quick data analysis of our Hatchbuck marketing emails, I found a few email subject lines best practices that might help as you are crafting your great emails!

How long should my subject line be? According to Sendgrid, 3 word subject lines have the highest engagement while 7 word subjects are the most common. What’s always important to remember is that mobile devices (where about 50% of your contacts are reading their emails) typically only display 25-30 characters.

Are there any keywords that will help my cause? ReturnPath did a study of their own and found that these 3 “types” of subject line keywords performed best:

  • Urgency: expiring, extended, hurry, running out
  • Benefit: best, cheapest, fastest, easiest
  • Command: add, buy, call, get

What else works? There are 3 other types of subject lines that perform well and are worth considering:

  1. Asking a question
  2. Using humor
  3. Offering a promotion

The one caveat here is that variety is the spice of life. Don’t do the same thing every time or you will wear out your list.

A Hatchbuck Study.

To confirm, deny, or illustrate these stats I decided to look at some of the great emails our marketing team has been crafting. I took a look at 15 different subject lines and their performance across 95,000 sends.

Here is what I saw.

Average Length: 4-5 words

Highest performing (>30% open): 2-4 words

Keywords (or “power words” as I like to call them)

  • First name
  • Growth
  • eBook
  • Winning
  • Skyrocket
  • Guide
  • Easier
  • Experts
  • More
  • Save
  • Solution

Highest Performing: First name, Save

“Types” of Subject Lines used:

  1. Personalized (with the contact’s first name)
  2. Hi, [Contact First Name]
  3. Description – straightforward explanation of what is in the email
    ex: The Marketer’s Guide to Hyper-Relevant Content
  4. Download – offering a piece of content
    ex: [eBook] Content Marketing Playbook
  5. Bait – enticing idea that will be answered in the email
    ex: We think you’ll like this winning marketing play
  6. Promotion – special offer
    ex: Save Some Bones

Highest Performing: Personalized, Promotion

So for the Hatchbuckers, our best subject lines are short, sweet, and personal. We also have seen great success with our promotions – maybe that’s because we don’t offer them that often!

What works best for you? The rule is to test, test, test. Always be looking at your stats to see how you can improve!