Inbox standouts: 9 great email subject line examples and why they work
The subject line is the most important piece of copy you’ll write for your email marketing strategy.
We don’t make this statement lightly. Body copy and CTAs are the meat and potatoes of your marketing emails, and you wouldn’t see clicks and conversions without them.
But you wouldn’t see any results without effective subject line copy—because it’s what gets someone to open your email in the first place.
In fact, we think subject lines are so important that we conducted research to define a few basic email subject line best practices, which found:
- Personalized emails earn higher open rates.
- Most great subject lines create a curiosity gap.
- Short subject lines that look complete on mobile perform better.
- Urgency and scarcity prompt people to open emails.
- Context rules all good email content performance—including subject lines.
- Emojis aren’t bad in subject lines, but use them sparingly.
- Thoughtful preview text can make a good subject line great.
But if you’re here more for inspiration, we’ve picked through a lot of our customers’ subject lines so we could highlight the ones that embody those first principles. Here are a few of our favorites—with details on what makes them stand out:
1. Supply uses an emoji to convey context
Subject line: This email is better than 👇
Most email marketers understand context, in theory—they know their emails are showing up in the flooded inboxes of overwhelmed, busy people.
But the marketers at shaving brand Supply go one step further than comprehension. With this cheeky subject line for BFCM, they make damn good use of an emoji to show they understand the context of the average inbox. With solid reinforcement from their preview text, Supply crafts one of the most creative yet simple subject lines we’ve ever seen.
2. Dagne Dover prioritizes mobile with a punchy subject line
Subject line: To you, from you
“Most email opens are happening on mobile devices, so it’s critical to think mobile-first when you’re writing subject lines,” says Dayna Scandone, principal customer success manager at Klaviyo.
“You should always be testing your email campaigns on desktop and mobile to ensure they’re showing up exactly how you want them to, and that includes the subject line,” Scandone adds.
You should always be testing your email campaigns on desktop and mobile to ensure they’re showing up exactly how you want them to, and that includes the subject line.
You don’t necessarily need a super short subject line to see high email open rates—the average word count is 7, according to our research. But at the very least, your subject line should look great on mobile.
Dagne Dover, the brand that creates “problem-solving bags for problem-solving humans,” demonstrates a mobile priority with this subject line that’s just 4 words long. It stands out in an inbox not only because it’s shorter than other subject lines, but also because it’s so concise and direct.
3. Beekman 1802 builds urgency for a free offer
Subject line: LAST CALL 📣 Free Mini Milk Drops
All caps, an emoji, and a freebie available for a limited time—these are the ingredients of a subject line that inspires a sense of urgency.
Assuming skincare brand Beekman 1802 sent out a couple emails before this one to communicate the offer, this is a great subject line for everyone on the email list who didn’t buy during previous rounds. If you’re sending last chance reminders like this, you’ll want to exclude people in the segment who already took action from previous emails in the series.
Word of caution: Be careful that the urgency and FOMO (fear of missing out) you communicate don’t use email spam trigger words—words and phrases that, when included in your company’s emails, can land them in your recipient’s spam folder and negatively affect your email deliverability.
4. Dossier creates a curiosity gap for customers
Subject line: ✨Something NEW is coming…✨
If you’re sending an email to customers—especially VIPs—what better way to hook them than with something new?
Fragrance brand Dossier evokes curiosity with this simple, clear subject line. It may not work on people who don’t have high purchase intent, but on the flip side, it can work really well on people who have bought before. (Ahem—this is why email segmentation is so important.)
5. Reverie’s subject line and preview text go hand in hand
Subject line: Are you washing your hair properly?
Preview text: How to do it right
As Toccara Karizma, CEO of Karizma Marketing, points out, “Solving a pain point in your subject line can work well to encourage email opens.”
Solving a pain point in your subject line can work well to encourage email opens.
Haircare brand Reverie hints at solving a pain point by asking a provocative question in their subject line and expanding on it with their preview text. It’s a great example of how to keep your subject line short while using the extra real estate of your preview text to widen the curiosity gap.
6. House Of Harlow 1960 plays into the popularity contest
Subject line: Our most popular necklace is back in stock!
If something goes out of stock quickly, it must be good, right? A subject line that says, “Our most popular necklace is back in stock!” makes customers want to check it out immediately. House Of Harlow 1960 is a well-known jewelry brand that uses this tactic to inform customers when a bestseller is available again.
7. Fly by Jing demonstrates empathy for tough holidays
Subject line: Want to opt out of Father’s Day?
Sauce and seasoning brand Fly By Jing thinks ahead of Father’s Day by thinking about people who may not want to celebrate it. With a subject line that hits home for many, the brand pulls people in with the most important marketing attribute: empathy.
8. OSEA gets personal with a unique discount nudge
Subject line: Your 10% Off Ends Soon!
Vegan skincare brand OSEA Malibu draws people in with the most powerful subject line tactic there is: personalization.
When we hear “personalized email subject lines,” we often think first or last names. But this simple subject line takes personalization beyond the surface level by using the email recipient’s unique profile data—in this case, an expiring coupon code—to encourage an imminent purchase.
9. Wildfang sends a friendly—and witty—reminder
Subject line: Did I just get ghosted?
Genderless apparel brand Wildfang pairs witty copy with personalization in the subject line of this browse abandonment email automation.
By combining a reference to the recipient’s unique web browsing history with a cute spin on a phrase from the world of dating apps, the brand crafts a question that’s hard for their millennial audience to resist answering in the form of an open.
What’s next: using AI as your subject line assistant
Inspiration before writing is always great, but you can take it a step further by using AI to generate inspiration on the spot. Learn more about how Klaviyo’s subject line AI can help you generate better emails that convert—at scale.
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