Latest / The Email Marketing Podcast with Fexingo: Newsletters, Open Rates, and Subscriber Growth / How Email List Subject Line Length Affects Open Rates
Transcript
- Lucas: So there's this stat that I keep coming back to: Mailchimp analyzed over 20 million emails and found that subject lines with between six and ten words consistently outperformed both shorter and longer ones by about 12 percent. Not a huge swing, but when you're sending to fifty thousand subscribers, that's six thousand extra opens. Luna: Six to ten words — that's like a tweet and a half. Did they break it down by device? I feel like mobile changes everything. Lucas: They did, and that's where it gets interesting. On desktop, longer subject lines actually held their own — forty to fifty characters still did fine. But on mobile, the sweet spot was even tighter: around forty-one characters, or about six to eight words. Anything over sixty characters dropped off a cliff — open rates fell by nearly 15 percent on phones. Luna: That makes sense. I know I skim subject lines on my phone, and if the first few words don't hook me, I swipe it away. Luna: Love a real example. What were they selling? Lucas: Project management software for mid-market teams. They'd been sending subject lines like 'New features that will help your team collaborate more efficiently.' Twenty-two words. Their open rate was stuck around 18 percent. Luna: Oof — that's a wall of text on a phone. Lucas: Right. So we tested a shorter version: 'Faster collaboration, new features.' Seven words. Same audience, same send time. Open rate jumped to 21 percent. That's a three-point lift — on their list of forty thousand, that's twelve hundred more opens per send. Luna: And I bet the click-through rate improved too, because the people who opened actually knew what they were getting. Lucas: Exactly. Click-through went from 2.4 to 3.1 percent — a 29 percent increase. The short subject line set a clearer expectation. Now, not every audience is the same, but the principle holds: shorter subject lines force you to prioritize the value prop. Luna: So what about emojis? Do they count as characters? And do they help or hurt? Lucas: Great question. Emojis count as two to three characters each, depending on the render. The Mailchimp study showed that emojis had a slight positive effect on open rates — about 2 percent — but only when used sparingly. One emoji near the end of the subject line worked. Two or more actually reduced opens, especially on older phones. Luna: So more is not better. That's consistent with the whole 'less is more' theme. Lucas: Exactly. And it's not just length — it's also the first word. Research from Litmus found that subject lines starting with 'Introducing' underperform by about 10 percent. Words like 'Your' or 'Free' can be either great or terrible depending on your list. Luna: That's why testing is crucial. You can't just copy a template from a blog post. Lucas: Right. And the best test is a simple A-B split on a subset of your list. Send version A with a short subject line and version B with a longer one, both going to 10 percent of your list. Run it for a day, then send the winner to the remaining 80 percent. Luna: That's a clean workflow. And you can iterate: test short vs. shorter, or with and without emoji. Lucas: Exactly. One thing we noticed with the SaaS company: after they shortened their subject lines, they also saw a reduction in unsubscribes from 0.5 to 0.3 percent per send. So the shorter, more direct language seemed to attract the right readers and repel the wrong ones. Luna: That's a double win — more opens and fewer people leaving. So what's the takeaway for someone listening who manages an email list today? Lucas: If you're not already, audit your last ten sends. Look at the subject lines and see how many are over sixty characters. If most are, try a six-to-eight-word version on your next campaign. It's a low-risk test that can pay off quickly. Luna: And if you want to go deeper, look at your mobile open rates specifically. Most email platforms break that out. Lucas: Right. And that kind of practical insight — testing something simple, seeing a real lift — that's exactly what keeps this show interesting for us. I know we keep it ad-free because we want to focus on what works, not on selling you something. Luna: And listener support is what makes that possible. If you've ever gotten a tip from this podcast that you actually used — even just a subject line tweak that boosted an open rate — a couple of dollars a month goes a long way. Lucas: Yeah, it genuinely does. You can find us at buy me a coffee dot com slash fexingo. That's buy me a coffee dot com slash fexingo. And if you've already contributed, thank you — it's what keeps this show independent. Luna: So to loop back: subject line length matters, but the real lesson is to test for your own audience. There's no universal perfect character count. Lucas: Exactly. What works for a B2B SaaS company might not work for a fashion retailer. But the process of testing is universal. Start with a hypothesis, run a split test, let the data decide. Luna: And keep an eye on those mobile numbers. We'll be back next week with another angle. Lucas: Until then, keep testing. Thanks for listening.