What makes the best email subject lines?

Short, personal, genuine

I recently analyzed 60,000 email subject lines to answer questions like, “Is shorter is better?” You know — just for fun. I learned some interesting things that might challenge your assumptions about what makes the best email subject lines.

First, subject length could matter, or, it could not — but mostly, not. You may see research to the contrary, as in this recent Buffer article. But I question the approach used in some of this research. To put it simply, comparing your view rate to my view rate is inaccurate since we have different lists, different audience demographics, different frequencies, and different subscription practices. Not to mention different email topics!

How I analyzed the best email subject lines

Instead of analyzing all 60,000 subject lines to see which ones performed best, I looked at a batch of 60,000 subject lines but only compared them to other subject lines from the same sender. In other words, I looked at the subject lines that gave individual senders’ view rates a lift over their average view rates. Specifically, I focused on emails that had at least 5 percentage points more views than average for that sender.

Thus, if someone consistently had view rates between 10% and 13%, I looked for her one email that got 18% or higher. If another sender generally had a view rate between 45% and 50%, I looked for a view rate of 55% or more before analyzing the subject line itself.

What I learned about the best email subject lines

  • Shorter subject lines often drive more views — IF the sender’s subject lines are typically very long. In the example below, the email with the shortest subject line got more views than the average email from this sender (10 percentage points more views). Note that content definitely plays a role as well. “Sad News” is undoubtedly compelling.

Best Email Subject Lines Short

  • Personal-sounding subject lines often get above-average view rates. In the example below, “A Warm Farewell” got more views than the average email from this sender (15 percentage points more views). The content of this subject line is also intriguing — we’re not sure who is leaving.

Best Email Subject Lines Personal

  • Some RSS to Email senders who use the exact same subject line every week see fluctuations of 10% in their view rates. Huh? (Clearly, it’s not just about subject lines.)

The bottom line

  1. Always share the most genuine content you can in your subject lines. Don’t oversell, and don’t clickbait it. Just let people know your content is valuable.
  2. When appropriate, make your subject lines personal. I don’t mean that you need to include someone’s name. But the best email subject lines that read like you have a personal relationship with your customers, or have news about you (and not your business), tend to lead to high view rates.
  3. Use the “Compare” tool on GoDaddy’s dashboard to get a big-picture sense of how your subject lines are performing. For example, select your 5-10 most recent emails, click “Compare,” and look at the “Viewed” tab. Do any of your emails stand out?
  4. If you find yourself slipping into a ho-hum subject line pattern, surprise your readers by shaking things up a bit!

Also published on Medium.

Image by: gfdnova1 via Compfight cc

Dean Levitt
Raised on a farm in South Africa, Dean moved to the United States to pursue a career in music, eventually finding his way to both Hawaii and the tech world. While growing his previous company, Mad Mimi (acquired by GoDaddy in 2014), Dean realized he had a passion for helping small businesses grow online. Dean is the CEO of Yala. Yala combines social media video ads with intelligent scheduling software making design and posting simple for small businesses.