Your email subject line is the first impression—and often the only one—you get. Whether you’re running an ecommerce store, sending out a newsletter, or promoting a service, a strong subject line can drastically boost your open rates.
In this guide, we’ll show you how to write subject lines that get clicked, share proven best practices, and give you real-world examples you can use or adapt.
Why Email Subject Lines Matter
Subject lines determine whether your email ends up being opened or trashed. According to Mailchimp, open rates can vary dramatically depending on how compelling your subject is. A few tweaks can mean the difference between a 10% and a 30% open rate.
10 Rules for Writing Irresistible Email Subject Lines
1. Keep It Short and Sweet
Most people read emails on their phones. Aim for 40–60 characters max.
Example:
- ✅ “Your 20% Off Code Is Inside!”
- ❌ “We Are Reaching Out to Let You Know About a Discount on Your Next Purchase”
2. Create Urgency or Scarcity
FOMO (Fear of Missing Out) is a powerful psychological trigger.
Example:
- “Only 3 Hours Left – Don’t Miss Out!”
- “Limited Stock – Get Yours Before It’s Gone”
3. Use Personalization
People are more likely to open emails that mention their name or interests.
Example:
- “John, You’ll Love These New Arrivals”
- “Based on Your Last Order…”
4. Ask a Question
Curiosity leads to clicks. Make the reader want to find the answer.
Example:
- “Struggling with Time Management?”
- “Want to Save Money on Your Next Trip?”
5. Offer a Clear Benefit
Tell your audience what they’ll get if they open the email.
Example:
- “Free Guide: 10 Ways to Double Your Sales”
- “Get More Done in Less Time – Here’s How”
6. Use Numbers
Numbers draw the eye and make the subject line more digestible.
Example:
- “5 Easy Meals in Under 30 Minutes”
- “3 Mistakes You’re Making With Your Website”
7. Create Curiosity
Be intriguing but not misleading.
Example:
- “You Won’t Believe What We Just Launched”
- “We Have a Surprise for You…”
8. Add Emojis (Carefully)
Emojis can boost open rates—but only if used sparingly and strategically.
Example:
- “???? Hot Deals Inside”
- “⏰ Time’s Running Out!”
9. Test Different Variations (A/B Testing)
What works for one audience may not work for another. Always test.
Tools to use:
- Mailchimp A/B Testing
- ConvertKit Subject Line Analyzer
- CoSchedule Headline Studio
10. Avoid Spam Triggers
Words like “FREE!!!” and “Make Money Fast” can land you in the spam folder.
Safe alternatives:
- Use “complimentary” instead of “free”
- Focus on value, not hype
Subject Line Formulas You Can Use
Try these fill-in-the-blank formulas to get started:
| Formula | Example |
|---|---|
| “How to ___ Without ___” | “How to Grow on Instagram Without Paying for Ads” |
| “Get Your ___ Before ___” | “Get Your Bonus Before Midnight” |
| “The Secret to ___” | “The Secret to Writing Better Emails” |
| “___ vs ___: Which Is Better?” | “Shopify vs WordPress: Which Is Better?” |
| “Don’t ___ Without Reading This” | “Don’t Buy a Laptop Without Reading This” |
Final Thoughts
Writing subject lines that get opened is both an art and a science. You need to know your audience, test often, and stay creative.
Remember:
- Focus on clarity over cleverness.
- Be concise.
- Make the reader want to know more.
Now go write subject lines that demand to be opened.
