What Are the Best Email Marketing Subject Lines?

Photo by Maksim Goncharenok from Pexels
November 22, 2021


From emojis to poetry, what type of email marketing subject line has the best chance of winning your customer's heart?

What makes good subject lines?

Imagine a day filled with nothing but emails, writing emails and clicking on coworkers emails, and dreading an email from your boss. For many of us, this is the reality of our work and home lives, and this means no mood for browsing the emails from a company we are vaguely interested in. 

What better way to reinterest users than the only thing they can see before they delete it? Every subject line matters, as it is the difference between deleting junk mail (with an additional hasty unsubscribe at the bottom), or opening up the email to see what piqued interest.

Subject lines are all the customers see at first, before all the pictures, fonts, and products. According to Optimonster, 69% of email recipients report email as spam based solely on the subject line, making it one of the most important aspects of email marketing. We’ll show you how to write the best email marketing subject lines.

1. Straightforward

A straight to the point subject line ensures users know exactly what will be inside of the emails. There’s no BSing or clickbait, and everyone knows what they are seeing when they open up the email. This is often used for notification emails, often akin to “Your order number is...” but occasionally straight to the point can have it’s own charm.

The customer won’t feel like you’re grabbing attention or demanding anything, rather you are merely informing. According to Mailchimp, this tactic often works better than cheesy lures. If there is a specific purpose for the email, then the subject line should be equally specific. This weeds out all doubt, and the user won’t be woefully disappointed when opening them up. Sometimes, the best subject lines are just what they say they are.

Examples include: “Yes, this is a fundraising email,” (Ai franklin) or “Here’s a 15% off coupon for you.”

2. Fear of missing out

Creating an urgency with a subject line is an easy psychological trick to get more opened emails. Two methods of urgency include time (Limited availability) and stock (limited amount of X left).

A scarcity tactic puts social pressure on users to just check and see what it is they will be missing out on. According to psychologists at the College of Art and Sciences, Emails that are time sensitive can have up to 22% higher open rate, and can be easily combined with any other type of email.

For every email marketer, scarcity is a must have. These perform among the best of subject lines for email marketing, and having a combined mixture of urgency and another type can make for an excellent subject line.

Examples include: “Site wide SALE, only 24 HOURS!” or “Get this before it runs out of stock...”

3. Mystery

This type of email is clear bait, like a cupcake in a beartrap. They can see the enticing cupcake in front of them, and just a vague enough statement with a curious hint can pull users in. Since it’s an email, curiosity does not kill the cat, it can’t be harmful to click open. A good mystery will leave users asking “What is this?” just enough to peek at the email. This is good for unwrapping or birthday surprises.

Examples include: “We got you a little something...” or “Shh-”

4. Open Ended Questions

What makes a great subject line? Questions that open up a conversation between the user and company can create interest. Users may open the email, wondering what the answer to the question was, or may have their own notions of what the answer is. A satisfactory open ended question is a perfect subject line for interesting emails. Remember, an open ended question must not be able to be answered with a “yes” or a “no.”

Examples include: “What happens after you quit your job?” or “Who was Wonder Woman’s role model?” (Strong Women Strong Girls)

5. Funny/Clever

Who doesn’t love laughter? A clever or funny subject line can easily snag the attention of a user. If it’s not to open up the email for the discount being offered, they will open it only to see what other clever tidbits and humor you plan to use in the email. Humans chase after pleasure, and laughter reduces pain and stress. The best subject lines for email marketing that include humor where appropriate entice users easily.

Examples include: “An Introvert’s Guide Back to the Office,” or “I like you more than my nephew...”

6. Personalized 

Personalized subject lines means more than just saying the user’s name. If you’re familiar with the target audience, this can mean using birthdays, the city they live in or by, or mentioning their interests and previous history.

According to optimonster, email subject lines that are personalized by including a name boost open rates by 10-14% across industries. A well thought out, personalized email can create feelings of intimacy. We want users to know, “we thought of you.” The best email marketing subject lines combine this type of personalization with other types mentioned in this blog.

Examples Include: “Happy birthday Linda - here’s 15% off!” or “Here’s some items we thought you might like!”

7. Pain Points

Although hitting where it hurts can be quite risky, if you know your audience well a pain point can make for an excellent subject line. Tread carefully with these types of topics, just as easily as these topics gain email opens, they can equally lose customers. Often these topics are there to shock or stir controversy, so knowing your audience well is a must before testing this type.

Examples include: “Your Marketing Sucks: Why you need to think local,” (Wordstream) or “Everyone is gay.”

8. Emojis

Emojis are an easy and fun way to spice up a subject line. According to Experian, Emojis can increase your email open rate by 45%. At the same time, too many emojis can also be hazardous. When using emojis, the best amount is just one. Too many, or two or more emojis feel like careless litter, and users are less inclined to look. A last thing to note, keep in mind different operating systems use different emojis, and may not have the intended look on every email system.

9. Punctuation/Capital letters

Like emojis, capital letters are meant to be used sparsely. By having an all caps subject line, it looks no better than spam and ends up in the litter box. 

Carefully choose which words are the most important when choosing what to capitalize, what words do you want your users to look at, or focus on? Capitalization IS LIKE YELLING, so it’s best not to have any. Whole words capitalized can easily trigger spam filters. Capitalize as normal such as the beginning of sentences and proper nouns, and if there’s to be a whole word capitalized ensure it is only one word to catch attention but not force it.

Similarly, excessive punctuation can be annoying. Users can look at emails with subject lines that have three or more exclamation marks and feel like they are being obnoxiously told what to do. According to Mailchimp, it’s best to have no more than three punctuation marks. Any more and the subject line itself may be too lengthy.

10. Use Poetry


Did that catch your attention? Writing out sounds can make for an easily eye catching subject line. Onomatopoeia is a clever and easy way to make for the best email marketing subject line.

Similarly, rhyming can easily make users raise eyebrows at a well worded subject line. Rhyming can be both clever and funny, which would pique curiosity to even the most stoic of users.

Finally, alliterating awes and amazes anyone. Using poetry to create a cleverly worded subject line can make for the best subject line, since even if it doesn’t make users laugh, it is still fun. It’s why we still get cheesy subject lines in our own inbox. They are often enough to make users snort and wonder what’s inside.


Subject lines can be difficult, but easy once these principles are put into practice along with A/B email testing. We suggest writing at least ten subject lines per email, and looking through open rates, and making sure audiences respond well to these.

If writing too many subject lines is time consuming, we have sent over 8,000,000 emails for over 50+ small, sustainably focused businesses who collaborate with our dedicated email teams. Knowing how to write an awesome subject line for your brand is just the beginning before readers get deep into your content! If you need help crafting your subject lines or anything else email, hit us up and we'll do our best to get you where you need to be.

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Written by

Jasper is an expert email marketer. He is passionate about helping sustainably driven businesses reach their marketing goes through beautiful, branded emails.