How long should my subject lines be, anyway?

If you often peruse email marketing statistics (which is perfectly fine, by the way, but maybe the kind of personal information you’ll want to gloss over at parties), you may have run across a fair amount of research on the length of subject lines. MailerMailer reported that shorter ones perform better than longer ones. Then MarketingSherpa’s research just came right out and said that 35 characters was the magic number. But we experimented with subject lines here at the Emma shop and found just the opposite – our longer subject line boasted both higher open and clickthrough rates than its shorter counterpart.

So I was thrilled to see some new research on subject lines hit the wires this morning, from Mediapost’s Email Insiders’ Summit. One of the conference speakers, Dala Quist, presented his own research about subject line length. He reinforced the idea that shorter subjects – 50 characters or so – garner better open rates, but he didn’t stop there. His research showed another spike in performance for subject lines around the 80-character mark. The slump in open rates happened in the middle range (60-70 characters).

From the article at MediaPost:

Research culled from 250 million messages sent over the past two years, with 660 different subject lines, has led him to believe that a 50-character subject line touting a “powerful” offer is appealing (30% off Spring Getaway flights to Florida on Delta).

And a longer 80-character-plus line describing a newsletter in enticing fashion works (Find out Secrets to Spice up your Barbecue this weekend and all Summer Long and enter to win a New Weber Grill.)

It’s great news for a couple of reasons – one, it helps me feel better about our own longer subject lines, of course, but second, it recognizes that the ideal subject line’s length depends on what you’re trying to accomplish with your campaign. If it’s an offer you’re promoting or a particular call to action you want people to take, shorter’s better. But if you’re using your email newsletter with an eye toward retention, relationship-building and content, a longer subject line will give you more chances to tease the content that’ll get your readers engaged with your email.

Not sure what’ll work for you? Try splitting your audience in half and try two different subject lines for the same campaign, and let us know how it goes…