Email Subject Lines: 9 Copywriting Techniques to Boost Open Rates

Email is still one of the most effective channels to engage, convert, and retain potential customers, but it’s getting harder to stand out in people’s inboxes. For this reason, writing engaging email subject lines has become more important than ever. By 2025, the number of emails sent and received globally each day is estimated to reach 376 billion.

Try using no more than five words in your subject line

Subject lines with fewer words tend to be more effective

• If the subject line needs to be longer than 5 words, put the most compelling information at the beginning
• It should be a short and simple hook to draw the reader in

Use Title Case

When the major words of the subject line are capitalized, it seems to add authority to the message.

• Try split testing two identical subject lines-one in title case and the other in sentence case-and measure the open rates for each version.

Use second-person pronouns

Emphasize how the reader will benefit from opening your email.

A well-crafted email subject line will boost your open rates

Copywriting techniques can help your emails stand out

• Use a combination of two or three of the strategies outlined here
• A/B test different versions, measure the results, and focus on what works for your unique business and audience

Combine personalization with conversational language

Address the reader by name, but keep the language informal and write like you’re talking to a friend

About the Author

Cara Berkeley is a blogger, investment property owner, and full-time marketing executive.

• She’s learned that thinking outside the box can make all the difference and shares tips and tricks on smart money management and investing on her blog, “Pennypolly”.

Sharpen up your unique voice

Use language that is unique to you and complements your personality.

• Humor and a unique copywriting voice will influence your customers to read more, and they will want to subscribe to your business if you have a unique voice.

Experiment with emojis

Including an emoji in the subject line can help your message stand out in an inbox.

• However, be aware that not all businesses are the same
• Try split testing two versions of the same subject line-one with an emoji and one without.

Use numbers in your email subject line

Include a statistic from a survey, a time-saving figure, the discount percentage figure, or the number of steps in your how-to guide.

• Break style guide rules by writing numbers less than 10 as numerals.

Add intrigue or make an honest promise

Use questions to build interest and promise to reveal how readers can achieve something.

• Make sure the actual email copy stays true to the subject line (e.g. “David, is your home priced to sell quickly?”).

Use the FOMO technique periodically

Use it to boost email open rates, but use it carefully and honestly.

• If you do it too often, it can seem inauthentic and repel potential customers
• Don’t promote a limited-time offer one week, only to offer a similar promotion the following week.

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