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6 Subject Line Formulas to Boost Email Open Rates (Plus Our Top 10 Subject Lines Ever), w/ Laura Palladino

Hey everybody! My name is Laura and I’m the Social Media Director for Ezra’s $100 million ecommerce brand, BOOM! by Cindy Joseph.

Email is a big part of our marketing strategy, and we send a lot of them.

In fact, since 2015 we’ve sent a total of 967 manual broadcasts to different segments of our list (that’s on top of the hundreds of thousands of automated emails we’ve sent).

Fortunately, Klaviyo lets us download all of our analytics into a CSV file, so we can see the clickthrough rates, opt-out rates, and bounce rates of every email we send.

So in today’s video, I want to go over some of our best-performing subject lines from these emails.

We organized them by open rate and removed any that went to under 100 people (super targeted emails are naturally going to have very high open rates). So these emails all went to large segments of our list and should provide enough data to give us some fun insights.

Keep reading for our top 10 email subject lines, plus get 6 subject line formulas you can copy to boost your open rates.

Things Influencing Email Open Rates Besides Subject Lines

First, I want to tell you about a few things that can influence your email open rates besides the subject line itself.

Your List: How “clean” is your list? Are you scrubbing (i.e., removing) the people who are not opening your emails?

Delivery Time: We’ve tested our delivery times. Most people think the best time to email your list is early in the morning, but that’s not always the case. It’s important to test your delivery time because that can influence your open rates.

Subject Line Length: Best practices state that you want your subject line to be between 6–10 words. Say what you have to say as quickly as possible because 47% of email recipients say they open an email based on the subject line, so you want to make sure you’re grabbing their attention.

Email Sender Reputation: This is a score assigned by an Internet Service Provider (ISP) based on the emails you send. This score is affected by factors like: Are people opening your emails? Are you sending a TON of emails and being spammy? Are you using email “curse words” or phrases like “Open Now!” or “% OFF!”? (Only use these occasionally or you can land in the spam folder and hurt your sender reputation.)

Looking at Subject Lines by Email Channel

Next, I want to talk about your email channels. (Don’t worry, we’ll get to the actual subject lines soon!)

You have two main email channels: your sales channel and your content channel.

And each of these has multiple sub-channels. For instance, you sales channel will include your product launches, flash sales, and holiday sales.

But you don’t want to be selling all the time. You need to give your subscribers value, too.

That’s why you have a content channel, which will contain sub-channels based on the kinds of content you create for your business.

Here are ours:

Between these two channels, we have an array of content that we send to our list.

Top 10 Email Subject Lines of All Time

First I’m going to show you our top 10 subject lines of all time — this includes sales and content:

Our #1 highest performing email of all time went out to 1,000 people and had an 83% open rate.

The subject line was, ALERT: About Your BOOM! Order.

This is what you might call a transactional email, which actually falls outside of the sales and content channels. These are emails that refer to a customer’s purchase, user account, or other transactions they’ve had with your brand.

You can see why this email had such a high open rate: the subject line is about their order. These transactional emails are naturally going to have higher open rates, but this one did exceptionally well.

Our #2 highest performing email of all time had the subject line, Attention: BOOM! Shipping Error.

This is another transactional email with a subject line that uses attention-getting words to get people to open. You don’t want to use this type of language too often or you’ll end up like the boy who cried wolf. Try to reserve these for very important emails.

Most of the other top subject lines are from our giveaways (no surprise there — people want to know if they won something!), as well as some content. But since I cover content emails later in this article, let’s jump straight into our top 10 subject lines from sales emails.

Sales Emails: Top 10 Subject Lines

These are the top 10 subject lines from specifically our sales emails.

You’ll notice most of these were sent around Black Friday, which makes sense because more people open sales emails around BFCM.

On top of that, we make sure to send these to a clean, targeted list of people with a history of opening our emails. We don’t just blast our whole list with a ton of sales emails because that could hurt our deliverability and lower open rates.

What I really want to show you are our content emails. I’m going to break down some of the subject lines, and give you 6 formulas you can copy in your own emails.

Content Emails: Top 10 Subject Lines (Plus Formulas You Can Copy!)

Here are the top 10 subject lines from our content emails:

The #1 subject line is 5 Ways Beauty Has Changed Thru History, with almost a 61% open rate going to 40k recipients.

You can look at these on your own, but right now I’m going to break down some of the subject line formulas that we use so you can copy them to boost your open rates.

6 Subject Line Formulas for Higher Email Open Rates

1. The Question
Ask the reader something, and make them really want to know the answer! A great way to use this formula is to look at the article or the piece of content you’re mailing and think of a question that the article answers.

Examples: Want to Look a Little Fancier Tonight? (35.26%), Are You Struggling with Your Age? (32.86%)

2. The Statement
Telling your subscriber something that’s relevant to your brand or to a piece of content. Make it interesting!

Examples: This is What Makes You Attractive (37.82%), You’ve Never Seen Me Model Like This (32.81%)

3. Curiosity
People are naturally curious, and we can use email subject lines to play on that. This is similar to the Question Formula, but it doesn’t necessarily have to be a question.

Example: From Hive to Jar: How Boomsilk is Made from Start to Finish (35.59%), You get the first sneak peek! (42.76%)

4. The “New”
When sending an email you always want to consider, “Why now?” Why are you sending this email to your list right now? And an answer that always works for that question is, “Because it’s new!” For this formula, be sure to use words like “NEW” in the subject line to attract attention.

Example: New Chicos Interview (42.76%)

5. The Quote
When we send out an interview or another piece of content where someone is speaking, we’ll often pull a quote right from the video or article and use it in the subject line.

Examples: “Take life one nanosecond at a time” (59.26%), “After facing anorexia as a teenager…” (54.31%)

6. The Listicle
We use this one a lot. A “listicle” is a combination of a list and an article, and it’s a really fun way to create new content and repurpose old content.

Example: 5 Ways Beauty Has Changed Throughout History (60.98%)

Important: Test Your Subject Lines!

I hope you use these subject lines and formulas as inspiration in your own email marketing, but don’t forget to test!

Different things work for different markets, industries and email lists.

We’ve tested emojis vs. no emojis, quotation marks vs. no quotation marks, long subject lines vs. short… That’s the only way to be sure of what works for your business.

Also, remember to segment your list and scrub it regularly to keep that deliverability up.

This has been Laura Palladino. See you soon!

[FREE] Watch Our Email Marketing Audit


In this free training ripped from Smart Marketer’s premium email marketing course, Social Media Director Laura Palladino gives you an in-depth look at how BOOM!’s monthly emails actually performed.

Learn what we did right, what we did wrong, and how to give yourself an email performance review to boost your own results.

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