How to Write Compelling Email Subject Lines?

How to Write Compelling Email Subject Lines?

In this digital world, emails are essential to digital communication. According to Statista, approximately 319.6 billion emails are sent and received per day all around the world. Interestingly, the number is expected to increase to 376.4 billion daily by the end of 2025.

Many marketers, entrepreneurs and business owners consider emails an effective way to reach their target audience. Companies can use email to promote products, offer discounts, and build customer relationships.

Writing engaging copy, a visually appealing design and a killer email subject line are essential to make your email marketing campaign successful. You will likely get a high email open rate if these elements work together.

Marketers struggle to write killer subject lines as they can create a positive first impression and encourage users to open, read and click your email content. Writing a compelling email subject line is crucial to ensure that your email stands out in a crowded inbox and gets opened by the recipient. Knowing how to optimise email subject lines can help you grab the readers' attention and convince them to open it and take action.

If you are wondering how to optimise your email subject lines to improve your email performance, here is a detailed guide on writing compelling subject lines that will get people to click through.

Why are Email Subject Lines Important?

Creating good email subject lines can help you attract more potential customers and grow your business. You can make your email marketing campaign a big hit by crafting engaging email subject lines. Some of the significant benefits of using compelling subject lines include:

• Create a powerful impact on readers
• Higher open rates
• Increase email engagement
• More conversions
• High profit

Tried and Tested Ways to Write Compelling Email Subject Lines

Don't Forget to Add Social Proof

Undoubtedly, it is the best trick to craft an attention-grabbing email subject line. Many email marketers are harnessing the power of social proof and using them smartly in the subject lines. You can also get a higher email open rate by using social proof. For example, you can add testimonials to your email content and show your potential customers that your services or products are high quality.

A study shows that 95% of shoppers read online reviews before purchasing. You can use testimonials to increase email engagement and open rate. Injecting social proof into your subject lines can get the reader's attention and encourage them to act. For example, “Hear it from our customers”.

In addition to testimonials, you can add different other types of social proof, including:

• Mention your collaborations and influencer partnerships    
• Stats from a case study
• The number of satisfied customers
• The number of subscribers
• The number of social media followers
• Highlight your awards
• Add an endorsement
• Include media mentions

Create a Sense of Urgency

When writing a good email subject line, creating a sense of urgency is essential to motivate people to take the desired action. Use phrases like “limited time offer”, “ends today”, or “5 hours only” to create a sense of urgency and encourage the recipient to open your email.

It is an excellent trick for eCommerce stores, but if you are not selling products, you can still use this tactic, such as a countdown timer, last chance, etc. Many email marketers use this trick and create a feeling of FOMO (fear of missing out) to add urgency to their subject lines.

So, next time you run an email marketing campaign, harness the power of the fear of missing out to encourage the recipient to open the email rate and take the desired action.

Keep it Short and Sweet.

HubSpot says approximately 41% of email views come from mobile devices. Make sure the email subject line is short so that it can easily be visible on the recipient's screen and that it quickly conveys the purpose of your email.

The ideal length of an email subject line is between 6-10 words (50 characters). Many email marketers recommend shorter subject lines to help mobile users quickly scan their emails and understand the message. According to a study by MailChimp, email subject lines with 50 characters have a higher email open rate (12%) and a higher click-through rate (75%) than those with wordy subject lines. So, keep it brief.

Personalise it

Use the subscriber's name in the subject line to add a personal touch to your email and make it catchy to them. Marketers are advised to learn about their subscribers' preferences, interests, jobs, dislikes, and locations. This strategy will help marketers to send more personalised email content that will convince them to complete the action.

Fortunately, many personalisation tools can help you personalise your email content and increase digital business revenue by 15%.

1. OptinMonster
2. Proof
3. HubSpot
4. MailChimp
5. Smartlead
6. Segment
7. Yup
8. Moosend
9. Episerver
10. BrightInfo
11. LiveChat
12. Qubit
13. Sailthru
14. Bronto
15. Evergage

Personalised email subject lines can strengthen your bond with subscribers and generate excellent results. So, use them wisely.

Go Beyond Names with Segmentation

Look, sticking their first name in the subject line is a good start, but let's be honest, it's the bare minimum these days. Everyone's doing it. If you really want to get clever, you need to go deeper with segmentation. The thing is, not all subscribers are the same, so why would you talk to them like they are?

Segmentation is just a fancy word for splitting your audience into different groups based on what they've done, or haven't done. This way, you can send them a subject line that actually means something to them personally. It shows you're paying attention.

• For New Subscribers: These lot have just joined the party. Make them feel welcome. Something like, “Alright, [Name]? Here’s what you get for joining us” works a treat.
• For Loyal Customers: These are your regulars. Treat them like VIPs. Try an exclusive subject line, “Just for you: A first look at our new gear” or “A little thank you for being a top customer.”
• For Inactive Subscribers: The ones who've gone quiet. You need to give them a nudge. A bit of curiosity works well, like, “Is this goodbye? We miss having you around” or “Still interested? Here’s a little something to tempt you back.”
• For Cart Abandoners: They were so close. A gentle reminder is all it takes. “Did you forget something?” or “Your basket is about to expire…” creates that bit of urgency without being too pushy.

Be Specific

Your subject line should convey what your email content is all about. Avoid using vague subject lines that mislead readers and don't provide any specific information about the content of the email. If you add an element of mystery, make sure it still gives the reader an idea about what's inside.

Remember that the content and tone of your subject line are also important factors to consider when trying to increase open rates. A clear and concise subject line that accurately reflects the email's content can grab the recipient's attention and encourage them to open it.

Use Action-Oriented Language

It is one of the best strategies to create a catchy email subject line. Use action-oriented language in your subject line to encourage the recipient to take action or follow the instructions. Use a clear call to action in the subject line to help readers understand what an email is all about. For example, instead of “Monthly Newsletter,” you could say “Get Inspired with our Monthly Newsletter.” Words like “join,” “download,” “register,” and “subscribe” can also be practical. Use a clear call to action in the subject line to encourage people to take action and purchase.

Use Numbers or Statistics

Including numbers or statistics in your subject line can make it more eye-catching and convey the importance of your email. Many marketers are using this trick in subject lines and are achieving great results. If you want to get your email noticed, you can use numbers or compelling statistics, as it is easier for the brain to process numbers.

A survey suggests that email subject lines with numbers and statistics generate a 57% higher open rate compared to those without using numbers. Numbers and statistics get your emails noticed, so demonstrate a clear message about your offer to increase the open email rate.  

Use Brackets to Provide Context

Right, here's a dead simple trick that works like a charm. Use brackets. People's inboxes are a right mess, and anything you can do to stand out and make their life easier is a win. Brackets act like a signpost, telling the reader what's inside before they even open the email.

It cuts through the noise and sets a clear expectation. They know immediately if it's a video to watch, a guide to read, or an urgent action they need to take. It’s all about saving them time.

• To announce content: [Video], [New Guide], [Case Study]
• To highlight an event or offer: [Webinar], [Flash Sale], [Last Chance]
• To signal an action: [Action Required], [Your Feedback Needed]

This is especially good for B2B stuff, where people are busy and just want to know what's what. It’s a small change that makes a big difference. Give it a go.

Ask Questions

Using questions in the subject lines is one of the best tips for writing compelling subject lines. This strategy will catch the readers' attention and pique their curiosity. Questions will inspire readers to open the email for an answer, eventually increasing email engagement.

Asking questions in your subject line can pique the recipient's curiosity and encourage them to open the email. For example, “Are you making these common mistakes in your business?”

Furthermore, a question can set expectations for the content of the email that help readers understand the purpose of the message. So, ask a question in the subject line to make users open the email.

Add Emojis

Adding emojis to your subject lines is another great idea to make them more compelling and noticeable. Many email marketers believe using little icons in your subject lines effectively catches the reader's eye. Emojis can add a playful and human touch to your subject line. Emojis can help your subject lines stand out in the crowded inbox when used perfectly.

Make sure to use the right emojis in the right way to convey emotions and tone effectively. Emojis can add personality to your email, making it more memorable and engaging. It's essential to use them in moderation and only when appropriate for the context and tone of the message. So, use them carefully and make sure they are related to the content of the email.

Consider Dark Mode and Emoji Rendering

Here's something a lot of people don't even think about. Dark mode. A huge chunk of your audience is reading their emails on a black screen, and your perfectly chosen emoji might look a bit naff, or worse, become invisible.

Some colourful emojis just don't play nicely with dark backgrounds. They can look weirdly bright or lose their shape altogether. The only way to be sure is to test it. Send a test email to yourself and check it on your phone in both light and dark mode.

If you want to play it safe, stick to simple, high-contrast emojis that look good anywhere. Things like ✅, ➡️, 💡, or 🎁 usually render well no matter the setting. It's a pro move that ensures your message looks good for everyone, not just half your list.

A Big No to Spammy Words

When writing a catchy email subject line, avoiding spammy words is essential, as these words can trigger spam filters and reduce the chances of your email reaching the recipient's inbox. Usually, spam emails include words such as “make $”, “reward”, “cash”, “100% free”, “earn money”, “50% off coupon today only!” etc. Don't use excessive exclamation marks, caps, punctuation, or any particular font that triggers spam filters.  

Ensure to avoid using these words in the subject line and the body. Clickbait subject lines make false promises or exaggerate the content of the email, which can lead to disappointment and frustration for the recipient.

A/B Testing Your Subject Lines

A/B testing your email subject lines is a valuable tool for improving the effectiveness of your email marketing campaigns and achieving better results. Strategies and practices that work for some companies may not necessarily work for your business. Testing your subject lines lets you determine what works best for your target audience.

A/B testing allows you to compare different subject lines and determine the most effective at getting recipients to open your email.So when you're A/B testing, what are you actually meant to be testing? Don't just chuck random ideas at the wall and hope for the best. Be methodical about it. Here are a few variables you should be putting head-to-head to see what your audience really wants.

• Length: Try a short, snappy subject line against a longer, more descriptive one. See if your audience prefers a quick punch or the full story.
• Tone: Put a straight-laced, professional tone up against something more casual or funny. This tells you a lot about your brand's relationship with your subscribers.
• Personalisation: Test a subject line using their name against a generic one. It seems obvious, but you should always test it for your specific audience.
• Question vs. Statement: See what works better, asking them something like, “Fed up with low open rates?” or telling them something directly like, “Here's how to fix your open rates.”
• Numbers and Emojis: Does adding a number or an emoji actually grab more attention? Test a plain text version against one with a bit of visual flair.
• Word Order: Even changing the order of words can have an impact. Test “Get 25% off this week” against “This week only: 25% off” to see which part of the message lands best.

You can identify which are most effective at generating clicks and encouraging recipients to act. It refines your messaging and optimises the content of your emails, which can improve the overall performance of your email marketing campaigns.

By testing subject lines before sending out your emails to your entire audience, you can save time and resources by focusing on the most compelling subject lines. The insights gained from A/B testing can inform future email marketing campaigns and help you better understand your audience's preferences and behaviours. In short, A/B testing and optimising your subject lines can increase email engagement, save time and resources, and help you better understand your audience.

Make Readers Feel Special

It is one of the best strategies to make your email subject lines more engaging. With the right choice of words, you can make readers feel special and compel them to convert to your emails. Making readers feel special in email subject lines can help increase engagement and improve the effectiveness of your email marketing campaigns.

Use words and strategies that create a sense of exclusivity, value, and personalisation. This strategy will help email marketers increase engagement and build stronger customer relationships. Here is a list of phrases you can use in the email subject lines to add a touch of exclusivity and personalisation.

• A Special Gift for you
• This is an exclusive offer for you
• For our valued customers only

Timing Matters

Believe it or not, timing matters a lot for email subject lines. The subject line is the first thing the recipient sees, and it can determine whether they decide to open the email. The time of day you send your email can significantly impact open email rates.

It is advised to send marketing emails during business hours when people are more likely to check their inboxes. However, it would be best to consider your audience and their schedules. For example, if your target audience is college students, they may be more likely to check their email in the evening or at night.

In addition, the day of the week can also have an impact on open rates. Studies have shown that emails sent on Tuesday or Wednesday have the highest open rates, while emails sent on weekends have the lowest. However, this can vary depending on your audience and their habits.

Be aware of the upcoming holidays and special occasions, and craft your email subject lines accordingly. You can also consider trending topics and use timely headlines to make readers click to read.

Set Clear Expectations

A well-crafted email subject line can set expectations for the content of the email and increase the likelihood that your email will be opened and read by the recipient. Please ensure the subject line accurately reflects the email's content and gives the recipient a clear idea of what to expect when they open it. Use specific and descriptive language in your subject line.

Avoid using vague language, be more specific, and say “New Policy Changes.” Keep your subject line concise and to the point. It is important to note that many email clients only show the first few words of the subject line. Make sure the essential information should be mentioned at the beginning.

Add a Human Touch

Adding a human touch to your email, subject lines can make your emails feel more personal and engaging. Craft a subject line as a human being; no matter how serious your brand is, using a conversational style to add a friendly touch is excellent. Using everyday language can make your email subject line feel more natural and less robotic. For example, instead of saying, “Don't miss out on our sale,” you could say, “Want to save some money?”

Personalising the subject line with the recipient's name is also great for grabbing readers' attention and making the email more personal. For example, instead of saying “Monthly Newsletter,” you could say, “Olivia, Check Out Our Monthly Newsletter.”

Adding a human touch to your email, subject lines can make your emails feel more personal and engaging, leading to higher open rates and better engagement from your recipients.

Use the Sender's Name

Using the “no-reply” sender name is one of the biggest mistakes companies make when sending emails. You can use a sender name that is familiar to the recipient. This could be the name of a person, a brand, or a company. Using the sender's name in the email subject lines can help increase the open rates and build trust with your recipients.

Use the same sender name in your emails to help build recognition and trust with your recipients. Use personalisation to make the sender's name feel more personal and engaging. For example, instead of just the brand name, you could use a specific person's name within the brand.

For example, instead of using “no*****@*********ny.com” as the sender name, use Jo**@*********ny.com. This can make your emails feel impersonal and lead to lower open rates.

You can combine the sender's name and subject line to create a compelling and engaging message. For example, “John from Your Company: 5 Tips for Increasing Sales.” Just be sure to use a recognisable name, keep it consistent, and use personalisation where appropriate.

Add a Sense of Humour

It's no wonder that humour allows marketers to connect with their audience. Brands can use this trick to build trust and make their email content memorable. Add a sense of humour to your marketing emails to brighten your subscriber's day and strengthen customer relationships.

The email subject line is the perfect place to convey your sense of humour to subscribers and give subscribers a reason to laugh and open the email. If done correctly, funny email subject lines can convince customers to buy and deepen their connection with your brand.

Convince customers to buy and deepen their connection with your brand.

When using humour as a communication device and improving your email campaign performance, use it thoughtfully. Understand your buyer persona to understand better the happiness triggers and what makes them smile. Stay true to your brand values, and avoid overdoing or misusing humour.

“Black Friday–On Saturday? – Go ahead, save. We're not looking.”

“GDPR ≠ Gosh Darn Pretzel Rolls”

“The underwear you didn't know you needed.”

“Deals That Make Us Proud (Unlike Our Nephew, Steve)”

“It's pronounced, “captcha.”

It's important to use humour judiciously and in appropriate situations. Try to maintain professionalism and not use humour that could be offensive or inappropriate.

Use Storytelling to Create Intrigue

Alright, listen up. People love a good story. We're all wired for it. A great subject line doesn't just sell, it starts a story that makes people want to know what happens next. You're creating an open loop, a bit of intrigue that they can only satisfy by opening your email.

This isn't about clickbait. It's about hinting at something valuable inside. Instead of just shouting about a discount, you draw them in with a narrative. Think about subject lines like, “It all started with one terrible idea…” or “The marketing mistake that almost cost us everything.” Don't you want to know more?

This approach is brilliant for case studies, personal newsletters, or any campaign where you want to build a proper connection. You're not just another company trying to flog them something; you're sharing an experience. That’s how you get people to not just open, but actually care about what you have to say.

Preview Text

A survey suggests that up to one-quarter of respondents read the preview text before opening an email. Preview text is the most crucial part of your email that deserves your attention. Preview text appears right near the subject line in the recipient's inbox. It is a summary or teaser of the email's content to help recipients decide whether or not to open the email. Many email clients such as Gmail, Outlook, and iPhone Mail app display the preview text alongside the subject line.

Mail app Preview text is typically limited to a few words or a short sentence, so keep it concise and to the point. This brief description is an excellent opportunity to engage your audience and encourages the recipient to take action. Use the preview text to highlight the most important or intriguing aspect of the email's content, such as a benefit or question the email will answer.

Please avoid using the same language in the preview text as the subject line, as it doesn't provide any additional information and can be redundant.

Make it Informational

When writing an email subject line, try to make it informational by telling something your audience doesn't know. You can add shocking statements or facts your audience is eager to learn more about. Informative subject lines help ensure that the content of the email is relevant to the recipient.

When recipients receive emails with subject lines that match their interests or needs, they are more likely to engage with the email. Your business can build trust with recipients by providing precise and informative subject lines. It shows that you value the recipient's time and want to ensure they receive relevant and valuable information.

For example: “5 Thanksgiving Facts to Know”, “YES! Claim Tax Deductions from Your Summer Vacation”

Final Words

The key to writing a compelling email subject line is to be clear, specific, and relevant to the recipient. Master the art of crafting engaging subject lines by following the above-cited practices and tips and take your email marketing campaigns to a new level of engagement and success.