How to Write Email Subject Lines That Get Opened

You’ve crafted the perfect email. The content is spot-on, the design looks great, but if your subject line doesn’t grab attention, it might never get opened. Your subject line is the first impression, and often the deciding factor between an open and a delete.

Why Subject Lines Matter

Your subject line is your email’s headline. It’s what subscribers see first, and it determines whether they’ll open, ignore, or unsubscribe.

Here’s why it matters:

• 47% of recipients open emails based on the subject line alone
• 69% report emails as spam based solely on the subject line
• A strong subject line can increase open rates, click-throughs, and conversions

👉 Related: What is email marketing?

Characteristics of a Great Subject Line

Clear and Concise

Keep it short and to the point. Most inboxes truncate subject lines after 50–60 characters, especially on mobile devices.

• Use simple language
• Avoid filler words
• Get to the value quickly

Example:

❌ “We wanted to let you know about our latest product update”

✅ “New Feature: Schedule Posts in Seconds”

Personalisation

Adding a personal touch can significantly improve open rates.

• Use the subscriber’s name
• Reference past behaviour or preferences
• Segment your list for relevance

Example:

“Sarah, your 20% discount is waiting!”

👉 Related: What is email segmentation?

Curiosity or Urgency

Spark interest or create a sense of FOMO (fear of missing out).

• Ask a question
• Use time-sensitive language
• Tease the content inside

Examples:

• “Are you making this SEO mistake?”
• “Only 3 hours left to claim your bonus”

Relevance to the Reader

Make it clear why the email matters to them.

• Focus on benefits, not features
• Use language your audience uses
• Match the subject line to the email content

Example:

“Free Social Media Calendar for Busy Business Owners”

10 Examples of High-Performing Subject Lines

Here are some real-world inspired subject lines that follow best practices:

1. “Your free guide is inside 📩”
2. “Don’t miss out—sale ends tonight!”
3. “We’ve got something just for you…”
4. “How to double your email list in 30 days”
5. “Oops! You forgot something in your cart”
6. “The #1 mistake small businesses make online”
7. “🎉 You’re invited: Free marketing workshop”
8. “Can we help you grow your business?”
9. “This tool saved me 10 hours last week”
10. “New blog post: 5 SEO tips you can use today”

A/B Testing Your Subject Lines

Even the best subject lines can benefit from testing. A/B testing (also known as split testing) allows you to compare two versions to determine which one performs better.

How to do it:

1. Choose one variable to test (e.g. wording, emoji use, personalisation)
2. Send version A to half your list, version B to the other half
3. Measure open rates, click-throughs, and conversions

Tools that support A/B testing:

• Mailchimp
• Campaign Monitor
• ActiveCampaign

Final Thoughts

Your subject line is your email’s first, and sometimes only, chance to make an impression. By keeping it clear, relevant, and engaging, you’ll increase your open rates and attract more attention to your content.