6 Tips to Craft a Compelling Email Subject Line

Whether you want to send out a survey to your customers, potential new clients or improve the response rate of your monthly newsletter, it’s crucial that you learn how to craft a compelling email subject line. After all, you could write the perfect email, but if it falls flat with a subject line that sounds like spam, it’s never going to see the light of day.

That said, if you’re having trouble creating eye-catching subject lines, you’ve come to the right place. Below, we’ve outlined some of our favorite tips on how to create a compelling subject that increases email open rates.

1. Be Concise

Most of the time, when people open their inbox, they don’t go down the list meticulously reading each and every subject line. Instead, they quickly skim through their emails and ignore the ones that don’t instantly stand out. This is why it’s important to cut the fluff and get straight to the point.

When your subject line is direct, it increases the chances that your recipient will notice it while skimming. Additionally, the act of writing a brief subject line shows that you respect the time of your recipient. Since all relationships are built on trust, if you’re reaching out to a potential client, conciseness is the best way to create a good first impression. 

For best results, keep your subject line under 60 characters. This gives you enough space to get to the point without sounding too long-winded. 

2. Open with a Question

Sometimes the best way to get someone’s attention is to ask a question. When you craft a compelling question, it sparks curiosity in your email recipient, urging them to open your message to find the answer.

Once you have their attention, either answer the question in the body of your email or even in subsequent emails thereafter. This strategy could even cause your recipient to look forward to your emails in the future. 

3. Incentivize

If it’s appropriate for the context, offering an incentive can go a long way in improving your email response rate. If you’re sending out a survey, for example, you may want to feature a discount code in the body of your email. Your subject may read something like: “Share your feedback to receive your 20% off discount code.”

When you offer your incentive, however, just be sure it doesn’t sound too spammy. Something like, “Click now for your chance to win a free iPad,” is likely going to do much more harm than good to your email response rate.

4. Personalize

When you take the time to personalize an email, it’s a small gesture that yields great results. Naturally, you feel more compelled to open an email when it’s from someone you know. If it’s obvious that the person or business emailing you doesn’t know who you are, you won’t feel as motivated to respond.

Adding a touch of personalization is easy. Simply do five minutes of research to find out more information about the person you’re emailing. Reference their first name in your subject line or something unique about them that you can relate to.

5. Test Different Subject Lines

Depending on the goal and audience of your email marketing campaign, your ideal subject line is going to look different. To discover which strategies work best for you, it’s essential to try out different tactics first-hand.

One of the simplest ways to test out subject lines is through A/B testing. To perform an A/B test, you create two contrasting subject lines, sending subject A to one group of people and subject B to another group. From there, keep track of the open and response rates of each email group. This will give you clarity as to which strategy works best for your purposes.

That said, don’t make the mistake of sending duplicate emails to your recipients. If they receive the same email twice only with different subject lines, it’s going to leave a bad impression.

6. Optimize for Mobile

These days, more and more people access their email from their phones. In fact, 60% of emails are opened via smartphone. Keeping that in mind, you will need to optimize your subject line for mobile users.

First off, as we mentioned before, you will want to keep your subject brief. Under 60 characters should do the trick. If someone is browsing from the phone and the subject line is too long, it can be difficult to comprehend.

Additionally, double-check your email to make sure that any images in your message are mobile-friendly. If your images are too large, it could make loading times longer for your mobile recipients. 

Finally, to make sure your email is mobile-optimized, send yourself a test email, then open it on your phone. If everything is looking good on your end, then you’re ready to go. 


When it comes to increasing your email response rate, it’s of the utmost importance to optimize your subject lines. You can do so through personalization, keeping your subject brief and by optimizing your email for mobile devices. 

That said, don’t be afraid to try out different techniques. Just be sure to monitor your open and response rates to determine what strategies work best for you and your business. For more information about improving your email subject lines, check out Chattermill’s infographic below.


A blogger by passion and working as a digital marketing manager in one of the leading digital marketing agencies of USA. Also, loves music, travelling, adventure, family and friends.