Do shorter ones get higher open rates?
Call it the Goldilocks Conundrum: What character count is “just right” for subject line length?
If ever there were a question with an “it depends” answer, this is it. Before writing subject lines for your next email campaign, check out this research.
What can recipients see?
The number of characters displayed by devices and email clients — the weird term we use for Gmail, Apple Mail and other email service providers —varies widely. For instance, according to the Nielsen Norman Group:
- Outlook displays 78 characters on a browser at the full width of a 15″ laptop.
- Gmail on an iPhone displays 36-38 characters.
- Yahoo mail displays 38-42 characters on an iPhone before truncating the rest.
To avoid getting your subject line truncated, the folks at the Nielsen Norman Group recommend that you limit your subject line to 40 characters.
30 to 90 characters “is the dead zone, and will reduce the chances of opens and clicks in an email.”
— Adestra
But while the average desktop inbox displays about 60 characters, according to a study by Return Path, mobile devices display just 25 to 30 characters. With more than half of your audience members opening your email via smartphone, doesn’t it make sense to make this your standard?
The argument for limiting subject lines to what people can see is that you retain control of the message. After all, you don’t want your truncated subject line to say “lice” when what you wrote was “license.”
But that might be too short …
Longer subject lines perform better.
Longer subject lines boost response rates, according to Adestra, a U.K.-based email service provider. Its analysis of more than 1 billion emails showed that subject lines of:
- 90 characters and more produced the highest response rates.
- 30 characters or less also performed well.
- 30 to 90 characters “is the dead zone, and will reduce the chances of opens and clicks in an email,” write Adestra’s Parry Malm and Mark Bonner, the report authors.
Why is longer better? You can communicate more benefits with more characters, Malm and Bonner write.
Longer subject lines perform better for B2B
So, consider using 90 characters or more to communicate more benefits, Malm and Bonner suggest. More details boost subject line performance when subscribers are highly targeted, according to research by Mailchimp.)
Short subject lines perform better.
Super-short subject lines also perform well, according to Adestra. Subject lines with:
- Word counts of one or two (5 to 10 characters) are most likely to gain opens and clicks.
- More than 14 words come in second in terms of performance.
- Two to 14 words reduce clicks and opens.
Super-short headlines perform best in B2B
So consider using fewer than 30 characters for snappy subject lines promoting an offer or requesting action, Malm and Bonner suggest. But stay out of the dreary middle when you write subject lines.
Here’s more about dueling research on email subject line length.
But does it really matter?
Subject line length is just one of many factors that affects open rates. In fact, subject line length accounts for 0.1% of email open rate variance, Phrasee calculates.
Subject line length accounts for 0.1% of email open rate variance.
— Phrasee
That’s hardly a statistical significance.
Return Path had similar findings: “Overall, our research indicates that there is actually no correlation between the length of a subject line and its read rate.”
And MailChimp found that “For most users, there is no statistical link between subject line length and open rate. But for subscribers reading your campaigns on mobile devices, shorter may be better.”
Test subject lines.
The solution? Before you press Send on your next email marketing campaign, test your short subject line against a longer one. And let your recipients tell you what’s just right.
Learn more …
- What’s the best length for social media channels?
- What’s the best length for web pages?
- What’s the best length for news releases?
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Sources: Kim Flaherty, Amy Schade, and Jakob Nielsen; Marketing Email and Newsletter Design to Increase Conversion and Loyalty, 6th Edition; Nielsen Norman Group, 2017
“The Art And Science Of Effective Subject Lines” (PDF), Return Path, September 2015
“True or False: Shorter Subject Line will give you Better Results,” upland Adestra, modified Oct. 17, 2019
Whitney Blankenship, 7 Email myths it’s time to stop following, Learn inbound, July 1, 2019
“What are some best practices in writing email subject lines?” MailChimp, Dec. 8, 2014
Parry Malm and Mark Bonner, “And the best subject line ever is …,” Adestra, 2012
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