Tips on Writing Catchy Email Subject Lines To Boost Your Open Rates

Tips on Writing Catchy Email Subject Lines To Boost Your Open Rates
01 July, 2021 • ... • 3577 views
Anastasia Igumnova
by Anastasia Igumnova

There is plenty of advice on how to improve your email subject lines. Let’s take a closer look not only at the most obvious ways like length, word choice, punctuation, and emojis but also the emotional side of the matter.

Simpsons giphy

Why Email Subject Lines Matter

How many emails in your inbox are ignored? What has to happen for a message to catch your eye?

A few relevant factors matter when it comes to open vs. ignore vs. mark as spam an incoming letter. It can be the reputation of the sender, the presence of “fw:” in the name, and most importantly, the name of the message.

According to statistics, 33 to 47% of recipients open messages in their inbox based just on subject lines for emails.

How To Write Good Email Subject Lines That Get Opened

So what are the components of that perfect subject line for email?

Be original. Or just be clear?

Compare these 2 subject lines.

  1. “Free Ebook: 15 emails everyone should send”.
  2. “Why aren’t you sending these 15 emails?”

The first one is pretty straightforward. The second one is more creative, even provocative. Can you guess which one turned out to be the conversion winner?

Conversion results
And the Oscar goes to... that humble (but very straightforward) subject line “Free Ebook: 15 emails everyone should send”. I was surprised too. Source:

These 2 examples above from a big email subject lines study by Sean Bestor clearly state that it’s better to be clear and understood than to be provocative and risk not being understood. But there are a couple of cases when you actually can take that risk, and probably even be rewarded.

  • You’re just starting email marketing campaigns. This means your subscribers do not know yet what to expect from you. You can set this expectation yourself. They will open your emails if you really grab their attention.
  • You’re reactivating the subscribers that do not open your emails anymore. If you were waiting for a moment to unleash that creativity within you, this is it. As it can’t get worse.

Do not underestimate emojis

Emojis can create that vibe you can’t have when using just words. However, only 7% of emails sent in the USA have emojis in their subject lines. The reason for this is that emojis might display incorrectly depending on the device.

Emojis might display incorrectly depending on a device
OMG, I would have a heart attack if instead of the fun mood I’m trying to create here people saw… a white square? Where is my *frustrated* emoji 😫 ? Source: Litmus.

You can certainly use emojis. But do it wisely.

  • Use it if it contributes to your subject line. For example, if an emoji strengthens your message and makes it deeper.
An example of emojis contributing to the subject line
This emoji — surprise with a pinch of helplessness — really creates the vibe here. When I saw it I kind of started to wonder, what exactly the problem was so that poor Rob ended up feeling this way

Keep it short

On desktop devices, there’s a limitation of 60 symbols for an email subject line. For mobile devices, it’s down to 30 symbols. Also, 3 out of 5 users check their emails on mobile devices.

Did you know that hardly 11% of subject lines contain less than 20 symbols (a study by Aweber)? That sounds like a good chance to stand out with a short subject line.

That said, we recommend keeping it short when it comes to writing an email subject line. However, do test different lengths, and, when testing, pay attention not only to open rates but to clicks, too.

an example of a short subject line
That’s probably the shortest subject line in my inbox. What Morning Brew meant here is that they introduced an FAQ section on their website, where their subscribers can finally find answers to all their questions

Use personalization

Personalization is when you just put your subscriber’s name in the subject line, sit back and enjoy your open rate going sky high, right? Well, not exactly.

According to the latest research (2020), personalized subject lines get only 2% higher open rates. Probably that’s because way too many brands put their subscribers’ names in the subject lines while sending emails with general content.

The reason for such low traction might also be that people sometimes make mistakes when typing their own names. They might even choose the wrong input field without knowing. And guess what? They’re not going to like it when they see an email like this:

a bad example of personalization


  • Do not put a subscriber’s name in all the emails. Do it only when the email you’re sending really contains a personalized offer.
  • Test how subject lines with or without names perform with your audience to be able to choose a strategy that fits you best

Put questions and other punctuation marks. Or not?

We recommend minimizing exclamation marks or even commas to make your subject lines easier to read. According to research by Mailchimp, it’s recommended not to exceed 3 punctuation marks in a subject line to not make it look like spam.

Question-based subject lines are more engaging and naturally attract more attention. Emails with a question mark in their subject lines get around 2% more opens than those without a question mark.

an example of email subject lines with question marks
The upper subject line with a question really makes me want to open it, the “for you” phrase is a game-changer here. The lower one: I have no clue who Martin is but now that you asked I really want to know what he did, so yes, I’m opening this email right away!

The emotional Approach to Email Subject Lines. Examples and Best Practices

Apart from those apparent tricks like making it short and funny or not overusing emojis, let’s think of human qualities that make people curious…those aren’t always something we are proud of, but they work impeccably in sales.

Yes, we’re talking about vices.

Of course we would love to call to the virtues, but, honestly, who would choose a subject line saying “Be generous, donate 1$ to help the needy”? over “Make $1 mln. in a week”?

Today we will put under the microscope 7 human vices and weaknesses that can season your mailings, teach you how to write email subject lines that get opened, and turn your mailing campaigns into financial virtues.

Vanity and envy

There are plenty of marketing services that help generate a title for an email automatically, even though they don’t teach you how to write a good subject line for email marketing. As much as they may work, let’s face it, no one wants to be one among many receiving those faceless generic messages.

Dale Carnegie said, “A person’s name is to that person, the sweetest, most important sound in any language.” Based on this, it is logical to conclude that emails named “Hey, Ana!” would do magic. And many marketers use this tactic:

Tripadvisor screen mail

TripAdvisor sent me this…How could I resist?

Still, according to a survey by GetResponse, personalized emails get opened only 5% more often than non-personalized ones. It doesn’t mean that you have to throw the idea in the bin. It might not do magic by itself, but in synergy with other tactics like segmentation, automation, and engaging content, it can add up to your arsenal.

I love me too gif

Envy is another influencing factor, as many can’t stand the idea that someone and not them has a brand new trendy dress.

Examples of ostentation-targeted email subject line best practice:

  • Guess: “Don’t wear last year’s styles.”
  • Sephora: “Products the celebs are wearing”
  • Kiehl’s: “Want Softer Skin in Just 4 Easy Steps?”


You’ll say: I am not greedy at all, but let’s be honest, who will resist an email having [FREE] or [50% OFF] in its subject line? Your subscribers most likely will not.

MDouglas greed gif


Some research suggests that emails with “free” in their name have an open rate of up to 18%. Offering your product or shipping for free, giving a discount, or making a promotion makes more loyal customers, even if they don’t open or follow each of such letters.

greed example

When I had an idea of creating my online course, I’d definitely not want to miss that free advice from Teachable

greed example 2

Getting 1,000 visitors per day on your blog. That’s what every beginner blogger is literally dreaming of! Sumo really nailed it with this subject line

More subject lines for emails using the words “free,” “discount,” “sale,” “gift,” “promo/promotion,” “off” (as in 30% OFF):

  • HP: “Flash. Sale. Alert.”
  • Guess: “25% off your favorites”
  • Rip Curl: “Two for two.”
  • Rapha: “Complimentary gift wrap on all purchases.”

Laziness and sloth

Sloth is another human weakness that comes in handy when you are out of ideas on what to put in the subject line of an email. Our ancestors’ survival depended on the amount of energy conserved. Despite the evolution, the instinct of energy preservation is still inside us.


With life speeding up, optimization, be it time, money, or effort, is becoming a hotter topic. Another thing is procrastination and laziness march in lockstep with the hectic lifestyle and the abundance of stimuli around us as an inner protest against this insane turmoil.

Whenever you receive a message promising to help increase productivity with no effort or to kill two birds with one stone, it’s tough to resist.

An example of an email subject line based on a reader's laziness
“Hacking” Instagram seems next to impossible. But what if somebody tells you they actually have 8 ways of doing it figured out for you and are ready to share them with you? I’d jump straight in!
An example of a subject line that uses laziness as a trigger to get you to open it.
The word “easy” does the trick here. Everybody wants high conversion rates. Nobody wants to admit that high conversion rates mean a lot of work. There must be an easy way somewhere… Oh, wait, here it is!

Here are a few more examples of good email subject lines using laziness as a hotkey:

  • Digital Marketer: “212 blog post ideas”
  • DigitalMarketer: “A Native Ad in 60 Minutes or Less”
  • “25-point checklist for the creation of the ultimate optin form”
  • Syed from OptinMonster: “Grow your email list 10X ⚡ faster with these 30 content upgrade ideas”.


The desire to learn and investigate is innate in humans. Exploration and looking for answers create new connections in the brain. Finding solutions brings satisfaction and pleasure and entices us to look for more rewards.

Kobo sneak peek

Kobo knows that being offered a sneak peek makes it hard to resist having a glimpse of what might be in store for you later on.

According to FinancesOnline, interactive subject lines have 70% higher conversion rates.

Targeting curiosity in your campaigns, you must keep in mind the importance of calling your audience to action. Leave a question unanswered, hint at something unconventional, leave a door open just enough to stir interest.

Examples of the best subject lines for emails calling out to curiosity:

  • Netflix: “What’s playing next, [insert name]?”
  • Bill Gates: “Why Melinda and I swing for the fences.”
  • Beauty Bay: “Guess what Olivia Buckland is wearing? 👀🔥”.

Pain points

Everyone has their pet peeves, your customers included. Knowing those weak points can be your most significant advantage. Translating to readers that your product can help solve their long-standing problems creates that bond between you and your client, shows them you understand them and really care.

pain point email subject line example

Here, most likely the recipient’s search history on the Pet Circle webpage showed interest in fighting fleas. Here we have a perfect example of how web-search analytics can help create customized email subject lines

The process is reciprocal — your subscribers open those emails and increase your ROI.

Here are a few email subject line best practices that offer solutions to solve pain points:

  • HP: “Stop wasting money on ink.”
  • Sephora: “Your beauty issues, solved”
  • Uber: “Since we can’t all win the lottery….”
  • Evernote: “Stop wasting time on mindless work.”

Social proof

Since childhood, we adopt thinking, behavior, and communication-based on other people around us, starting with our parents. However, it comes with a price: we become dependent on other people’s opinions, acceptance, and social proof.

social proof black mirror
The Nosedive episode, Black Mirror series, is about being assessed in social media taken to an absurd level

In 1984, famous American psychologist Robert Cialdini wrote a book called “Influence: The Psychology of Persuasion.” With the book, the term “social proof” was born, encompassing the idea that people imitate the behavior of others to decide on how to behave themselves.

© Robert Cialdini.

The greater the number of people who find any idea correct, the more the idea will be correct….

According to Cialdini, social proof or consensus belongs to the six principles of persuasion: reciprocity, consistency, authority, liking, and scarcity effectively used by salespeople, email marketing included.

Social proof example
Here we see how the desire to follow a group and be accepted by others as one of their own, is put into action

Get inspired on what to put in the subject line of an email by these brilliant lines appealing to the need for social proof:

  • Patagonia: “Top reviewed styles from customers like you.”
  • Yummly: “Most Popular Recipes this Week”
  • Target: “Moms are loving these fave maternity looks.”
  • Foodtalk: “They call this bread heaven on earth.”


FOMO or Fear Of Missing Out is a relatively new phenomenon. It appeared at the beginning of the 2000s to describe a feeling of social anxiety. It stems from the idea of others having fun experiences in the absence of the FOMO-struck person. It is primarily common among millennials.

Usually, FOMO refers to missing out on something potentially rewarding. It can be instigated by others actively sharing their cool experiences on social media or ads promoting some amazing last-minute offers and urgency.

fomo nobody cares

Don’t they? Source: Unsplash by Sigmund

According to statistics, 60% of people make purchases because of FOMO, mostly within 24 hours.

The concept of FOMO is widely used in marketing and helps create email subject lines that work. Travel, entertainment, and even food FOMOs make people click on those ads and banners even if they don’t really need what is offered.

FOMO example

Here are some examples of great email subject lines using FOMO:

  • Les McKeown: “the DEADLINE is now…”
  • Urban Outfitters: “Clock’s ticking ⏲ 50% OFF 500+ items.”
  • Torrid: “BOGO free clearance is over in 5…4…3….”
  • The Spinsterz: “It’s there and then it’s GONE. POOF. 💥”

Key takeaways

Don’t overdo it.

  • In most cases, a straightforward subject line will get you more opens than a creative one.
  • Only put an emoji if it will strengthen your message.

Keep it concise and clean.

  • Make it short to stand out (especially for mobile users).
  • Limit your punctuation marks to 3 tops.

Personalize wisely.

Only put a name in the subject line when the email itself contains a personalized message.

Use an emotional approach to your subject lines.

In the ocean of hundreds of dozens of emails landing in people’s inboxes every day, choose to stand out. Create your subject lines with an emotional approach in mind to get people interested/curious/scared to miss. Show that you know that answer, that you have that solution they’ve been longing (or too lazy) to get. Get inspired by the examples we listed above.

01 July, 2021
Article by
Anastasia Igumnova
Digital nerd and bookworm.
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