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How to Write Best Subject Lines for Open Rates?

Written and researched by experts at AvadaLearn more about our methodology

By Sam Nguyen

CEO Avada Commerce

Drive 20-40% of your revenue with Avada
avada email marketing

Do you want to increase your email campaigns’ open rates? Email marketers with high-performance craft email subject lines that subscribers simply just can’t resist.

You already know that people have busy inboxes, and you have to compete against at least 121 emails per day an average office worker receives. And you also know that the only way to get more traffic and conversions for your email campaigns and ultimately sales is to stand out with great email subject lines.

In this article, my goal is to help you learn and understand the mechanics behind the best-performing subject lines and the examples that many industries can use for a great result. Let’s begin with a great starting point by showing you how to write the best subject lines for your emails.

How to write the best subject lines for a high open rate

How to write the best subject lines for a high open rate
How to write the best subject lines for a high open rate

Your subject line is the first (and even the last) impression on your subscribers. In many ways, the email subject line is just as, if not even more important than the email body. After all, no matter how fantastic your newsletter is, it will be worthless if it can never see the light of day.

Here are the components that I repeatedly found among top-performing email subject lines, so feel free to copy and apply to your campaigns for a high open rate.

Leverage words proved to boost email open rates

When you research email subject lines, you will soon dig up words, terms, and emojis that are highly likely to positively influence the open rate when you use them in the subject lines. Further analysis suggests that you can get the best open rates by using at least three or more of these words, terms, symbols in your subject line.

Words that can increase the open rate when including in the email subject lines are:

  • % off

  • 24-hour giveaway

  • About

  • Add

  • Advice

  • Available

  • Back in stock

  • Celebrate

  • Congratulations

  • Exclusive

  • Expiring

  • Get your

  • Great deals

  • Important

  • Last chance

  • Lastest

  • Limited time

  • Monthly

  • News

  • On sale now

  • Plus

  • Promotional

  • Register

  • Review

  • Soon

  • Special

  • Still time

  • Thanks

  • Today only

  • Tomorrow

  • Update

  • Upgrade

  • Voucher

  • Wonderful

  • Yesterday

Remove words that can reduce the open rate

Just as you have words that can typically increase the email open rates when using in the subject lines, there are also words that can negate those opens as well. The best practice is to use none of these words, terms, and symbols in your email subject lines.

Here is a shortlist of words and terms that you should avoid using in your email subject lines:

  • 100%

  • #1

  • Access

  • Announcing

  • Alert

  • Apply now

  • Bargain

  • Being a member

  • Best price

  • Billing

  • Budget

  • Cancel

  • Celebrity

  • Dear friend

  • Discount

  • Download

  • Eliminate debt

  • Fantastic deal

  • Free

  • Get ready for

  • Increase sales

  • Incredible deal

  • Join millions

  • Lowest price

  • No cost

  • No credit

  • No obligation

  • Once in a lifetime

  • Perfect

  • Problem

  • Risk-free

  • See for yourself

  • Success

  • Special promotion

  • This isn’t spam

  • Why pay more?

Include a number

Include a number

Including a number in your blog post subject lines can increase the click-through rate by 206%, according to research by CoSchedule.

Even though the research above refers specifically to blog posts, email subject lines serve a very similar purpose: Help increase clicks from the desired place (email inboxes, blog post category pages, or social news feeds, etc.).

Much like blog post headlines, having numbers in your email subject lines can increase the email open rates. You probably have clicked on a blog post that has numbers in its headline, right? (10 ways to improve the traffic to your eCommerce site, thing like that)

A recent study analyzed 115 million emails and suggested that email open and reply rates can be increased when a number is included in the subject line. Numbers are the type of data that gets your emails noticed and demonstrates a straightforward message about the offer inside the email while setting the right expectations for your recipients, helping draw them in.

So, try to include at least one number in the subject line, and you can boost your email open rates.

Keep the right character length

While many email marketers differ their opinions on the topic of email subject line length, everyone agrees on one thing: You should keep your email subject lines short.

About 50% of all emails are viewed on mobile devices nowadays. iPhones can show about 35-38 subject line characters in portrait mode, and Samsung phones can show roughly 33 characters in portrait mode.

With that information in mind, make sure 50% of your subscribers who will view your email on their smartphones can actually read the entire email subject line when scrolling through the inbox.

The best practice for subject lines is to be 17-24 characters long. That is the magic number to most likely boost your email open rates.

Also, use a short number of words in your email; no one can read for too long. Your email subject lines should be about only 3-5 words to boost the open rate.

Put an emoji in the subject line

Brands that are using emojis in their email subject lines have seen a 56% increase in the unique open rates. This isn’t a wild guess anymore; we’re really seeing great potential in emojis. Despite your feeling for emojis, you should use them in your emails and add a little bit of nice flare and more attention-getting elements for your campaigns.

If you don’t know where you can find emojis, then here they are:

Mac: Press Control + Command + Spacebar to access the emoji panel.

Windows: Press the WIN +. (the period punctuation mark) to access the emoji keyboard.

If these suggestions don’t work for you, you can search emojis on Google and get thousands of websites to copy and paste.

I suggest you use 1-4 emojis in the email subject line to boost your email open rates.

Test title case for the subject lines

Research suggests that writing subject lines in the title case can be effective in boosting your open and reply rates.

The psychological reason behind the email title case’s success is the perception of authority. Even something as simple as using a title case in the subject line instead of all lower case or sentence case is an authority badge that your brand can take advantage of.

It is like you show up in a suit in the inbox instead of wearing a pair of shorts.

What does the subject line in the title case actually look like?

  • Lower case: the best email subject lines for eCommerce companies

  • Sentence case: The best email subject lines for eCommerce companies

  • Title case: The Best Email Subject Lines For Ecommerce Companies

Use the right tone for the right audience

Your best bet for creating fantastic email subject lines starts from understanding your audience intimately. This is a major aspect of success for pretty much all fields of online marketing, and while you can find it a bit tougher in a limited field like an email subject line, matching your messages with the audience’s interests is essential if you want to achieve solid open rates.

Most successful email subject lines rely on having a conversationalist tone to attract more opens from recipients. Many sites like Upworthy and BuzzFeed are known for super-successful clickbait headlines and take advantage of a conversational, casual tone. If your email subject line can talk to the audience in their preferred tone, you are sure to have a better open rate.

Bonus tip:

Preheaders are fantastic to complement your subject lines. Preheaders can summarize the content of your emails for added enticement. Your recipients get a chance to preview your emails, even while they are still unopened in the inbox.

Preheaders are the tool you need to hook the readers, compelling them to open your emails. Also, sending emails with subject lines and preheaders can boost the campaign’s open rates by 7%, so you should add this practice to your email marketing effort and see greater opens and return on investment from your emails.

Whether your subscribers open their emails on desktop computers or mobile devices, preheaders add more space to hook your readers and impress with your email content.

The best email subject lines to skyrocket your email open rates

The best email subject lines to skyrocket your email open rates
The best email subject lines to skyrocket your email open rates

With all the tips above, I’m sure you have noticed that the best way to have amazing subject lines is by leveraging psychological principles and human tendencies. Here are examples of the best subject lines to have better open rates and the proven mechanics behind their success.

Best email subject lines to trigger curiosity

People have a natural desire for knowing the unknown - we don’t like having knowledge gaps. You can leverage this to trigger curiosity among recipients by making your subject line open-ended so readers will be curious to open. It works like a cliffhanger that people can only be satisfied after opening the email.

You can make your subscribers curious by asking them a question, promising an interesting experience, or simply stating something that sounds strange or unfamiliar to them.

Here are some fantastic examples of email subject lines that induce curiosity:

  • “Last Day For You To See What This Mystery Email Is About” - GrubHub

  • “Don’t Open This Email” - Manicube

  • “What They Eat In Prison” - Thrillist

  • “Rough day?” - Sephora Beauty Insider

  • “Final hour! Want to save 50%?” - Banana Republic

  • “10 bizarre habits to make you richer” - Refinery29

  • “A surprise gift for you!? {unwrap}” - Mary Fernandez

Some other ideas for curiosity-inducing email subject lines are:

  • A match made in…?

  • Smartest investment ever?

  • The “Post-COVID” reboot?

  • Ready to look like this in summer?

  • 10 items every boy should have

  • Got a few bucks to spare?

  • Is this the hottest item for the beach?

  • Check out our new “collection” [PICS]

Best email subject lines to trigger FOMO

We have a deep and inherent terror of being missing out or left behind. Once, that flock mentality was people’s survival instinct, but now it is a fantastic strategy for email subject lines to get recipients to open campaigns. You can use FOMO in your email subject lines by adding an element of urgency (limited time) or scarcity (limited availability).

In fact, email subject lines with words that imply time sensitivity are proven to increase email open rates. Think of words or phrases like “urgent”, “breaking”, “get it soon”, “important”, or “alert”, etc.

Here are some fantastic subject line examples for emails that can leverage the fear of missing out:

  • “You’re missing out on more points.” - JetBlue

  • “[URGENT] You’ve got only ONE DAY to watch this…” - Digital Marketer

  • “Uh-oh, your subscription is expiring” - Warby Parker

  • “Elena, Earn double points today only” - Jersey Mike’s Subs

  • “Ends Today! 36-Hour Outlet Sale. Hurry, this is your last chance” - Coldwater Creek

  • “Tonight only: A dream for denim lovers” - Guess

Some other ideas for FOMO-inducing email subject lines are:

  • [LAST CHANCE] 78% off sale ends today!

  • REMINDER: $1000 prize gone at midnight

  • Last chance to try our products for FREE!

  • [LIMITED TIME] The best sundresses are on sale!

  • [FLASH SALE] Today’s best deals on electronics

  • The lowest price EVER for sunglasses

Best email subject lines with humor

If your email subject lines can make your subscribers laugh, they’ll have to open your emails. After all, we all have read an email subject line that tickles the funny bone and just felt the urge to read it. Funny friends are hard to pass by.

Being humorous requires you to have a bit more creativity and thought about your audience, but it can definitely pay off in terms of the email open rates.

Here are some email subject lines with a great sense of humor to make the subscribers laugh and open:

  • “We Like Being Used” - The Muse

  • “Licking your phone never been so good” - OpenTable

  • “Where to Drink Beer Right Now” - Eater Boston sent this email at 6:45 am on a Wednesday

  • “Pairs nicely with spreadsheets” - Warby Parker

  • “Deals That Make Us Proud (Unlike My Nephew, Steve)” - Groupon

  • “Boom shakalaka! Let’s get started.” - TicTail

  • “As You Wish” - UncommonGoods

  • “Yes, I’m Pregnant. Stop Staring At My Belly Now” - Baby Bump

  • “NEW! Vacation on Mars” - Gozengo

Some other ideas for funny email subject lines are:

  • Look what you’ve done now…

  • Just scratch n’ sniff your way to deal haven

  • Please Touch Me! One-button Coupon Awaits!

  • How to Live Forever

  • Is That Your Final Offer? We Have Better!

  • Discover the New Frontier Of Shirts For Nerds

  • Your Clothes Suck! Here Is How to Improve

  • Everyone Is Gay: Best Items For Pride Month

  • Cloudy with a Chance of 50% OFF

Best email subject lines for vanity

We all have a bit of vanity. People want to be loved, accepted, and respected by others. It’s just an essential part of being human.

So, some of the most clever email subject lines leverage vanity to get recipients to open the emails. If you want to try this, you can either promise something that can make the subscribers look better compared to their peers or evoke the fear of feeling shamed.

Here are some fantastic examples of email subject lines that can leverage vanity for your brand:

  • “Don’t EVER wear last year’s styles.” - Guess

  • “Your Butt Looks Great in These Workout Pants” - Fabletics

  • “Age-defying beauty tips” - La Mer

  • “As worn in the World Series” - Rapha

  • “Products the most famous celebs are wearing” - Sephora

  • “How Have You Changed Since the Third Grade?” - Jeremy Gitomer

Some other ideas for email subject lines that can create vanity among subscribers:

  • Get Ready. You Can Keep the Pie Off The Thighs Returns.

  • 10 items you should have to look like Kim Kardashian

  • Gift Inspiration For The Best Friends

  • Don’t Be The Outcast In The Party! Wear These Now!

Best email subject lines to sound mysterious

As Scooby-Doo or Sherlock Holmes can tell you, people like to have a little mystery in their lives. Your email subject lines can give readers a little taste of something intriguing, which might cause them to bite. And your open rate just keeps going up like that.

However, be careful not to be too mysterious. If readers feel like they need to spend extra work on solving your puzzle, they may get frustrated and leave the emails without advancing into the step you expect.

Here are some fantastic examples of email subject lines that can make your brand more mysterious and get subscribers to open the emails:

  • “It’s all over on December 15th, hurry up!” - ePrize

  • “Come back today” - Netflix

  • Steal these looks at a discounted price

  • The napkin that cleaned up a $299k mess

  • $55 today, $4889 tomorrow

  • Bad news

Best email subject lines to target pain points

If you understand your buyer persona, you would know their most significant pain points, without a doubt. Then use those pain points to make subscribers open your emails by solving their problems for them.

Here are some fantastic examples of email subject lines that can bring out the subscriber’s pain points and offer suitable solutions from your company.

  • “Where do all these toys go?” - IKEA

  • “Your beauty issues solved” - Sephora

  • “How to Survive The Next Overnight Flight” - Thrillist

  • “Stop wasting your money on ink” - HP

  • “Cute and affordable fashions: Wanted” - Guess

  • “Stop wasting your time on mindless work” - Evernote

  • “Learn a new language with only 5 minutes per day” - Duolingo

Some more examples of email subject lines that offer solutions for the recipients’ pain points are:

  • Your checklist for creating the best winter outfit

  • 12+ Christmas gift ideas that ship under 24 hours

  • Steal these templates to advance your email marketing

  • How to dress for an interview (and which to buy!)

  • Get More Space In Your Closet With These Easy Fixes

Best email subject lines to retarget customers

You send retargeting emails to subscribers when they are unable to complete a step or an action in your sales funnel (for example, when they abandon the cart or fail to continue the subscription after the free trial). These retargeting emails serve to bring your recipients back to the sales process. This is a large source of revenue that you don’t want to lose.

You can write fantastic retargeting email subject lines by overcoming the consumers’ objections, offering a gift to sweeten the deal, or alerting buyers that something negative is going to happen if they don’t act soon.

Here are some excellent examples of email subject lines to retarget your customers:

  • “Hey, forget something in your cart? Here is 20% off.” - Bonobos

  • “John, your Envira account is on hold!” - Envira

  • “Did you miss out on some of our newest features?” - Animoto

  • “We are not gonna Give Up on You!” - Vivino

  • “The price just dropped for something in your cart” - Target

Some more fantastic examples of email subject lines to retarget customers and win them back are:

  • Your accounts have stopped working

  • We are deleting your subscription

  • The items in your cart are pretty sad right now

  • We Miss You, A Lot

  • Use This Coupon And Buy Your Wishlist Items!

Best email subject lines with a personal touch

Best email subject lines with a personal touch
Best email subject lines with a personal touch

Personalized email subject lines (just by including a name) can boost your campaigns’ open rates by almost 10 to 14% across industries.

But it is not the only idea to include your subscriber’s name in the emails. You have many other ways to make your email subject lines more personal such as using casual language, sharing something personal, or using a copy that implies friendship or familiarity.

Here are some examples of personalized email subject lines that can get attention from recipients:

  • “Elena, check out these hand-picked looks” - Guess

  • “John, do you remember me?” - Bonnie Fahy

  • “Happy Birthday Elena– Surprise Inside!” - Rent the Runway

  • “Are you coming?” - John Lee Dumas

  • “Quick favor?” - Jon Morrow

  • “Vanilla or Chocolate?” - Brooklinen

  • “Thanks for helping us” - Revolution Tea

Some more ideas of personalized email subject lines that you can steal for your email campaigns are:

  • We love you, Elle

  • Crazy Invitation, I am Going to Give You This Coupon

  • Free this Friday at 12 pm John? Something Big Is Coming

  • Two sundresses for you and your friends (on us)

  • Best of Liverpool: Salon and more

  • Don’t miss out - Private Class For Two People

  • 9 underrated restaurants near you

The best way to personalize your email subject lines is by segmenting your subscribers based on attributes like locations, actions, buying behaviors, and more. By using an app like AVADA Email Marketing, you can automate your emails for different segments of audiences and tailor your message to make them open your emails more.

Best email subject lines that are straightforward

When in doubt, simply make your subject lines straightforward. Contrary to what people might think, “boring” subject lines that are not so mysterious can actually convert well for companies.

The key to making this subject line tactic work for your email list is by consistently providing value in your emails. Don’t send an email unless you have something worth saying to the subscribers: always make sure that your email campaigns are packed with value. If you can do this, your subscribers will open your emails no matter what your subject line says.

Here are some examples of fantastic email subject lines that simply get straight to the point and let readers decide to open more quickly:

  • “Hey” - Barack Obama

  • “Best coat ever” - AYR

  • “Yes, this is a fundraising email” - AI Franken

This is simple to do, and I recommend every company to try it out with their email subject lines. If you don’t know where to start, simply being straightforward can help your emails get noticed even better. After all, people have a lot to read in their inboxes, so your subject line tactic can actually help them browse better.

Some templates of straightforward subject lines that you can use right now are:

  • [Company Name] May 2021 New Collection!

  • [Company Name] Our Weekly Sales & Marketing Newsletter

  • Happy Holidays from [Staff or Company Name]

  • Invitation from [Staff or Company Name]

Final words

That’s it! I hope you found this guide on the best email subject lines to increase the open rate helpful in creating your next email campaign. If you did, bookmark this article so you can always find inspiration in handy to craft your email subject lines.

Now it’s your turn. Go ahead and choose one subject line from the examples above to modify or make a new one of your own. You should also try incorporating some of the top keywords for subject lines to boost your campaign’s open rates and even more positive results.

Sam Nguyen is the CEO and founder of Avada Commerce, an e-commerce solution provider headquartered in Singapore. He is an expert on the Shopify e-commerce platform for online stores and retail point-of-sale systems. Sam loves talking about e-commerce and he aims to help over a million online businesses grow and thrive.