SocialStruggling to write compelling subject lines for your email campaigns? You’re not alone. In today’s crowded inboxes, your subject line is your first—and possibly only—chance to grab attention. If it doesn’t stand out, your email may never get opened.
Below, we break down 8 powerful subject line formulas that consistently increase open rates and conversions. Customize and tweak them to suit your audience and campaign goals.
1. The Question Subject Line
Why it works: Questions naturally prompt readers to reflect and engage. They spark curiosity and invite clicks.
Examples:
- Do you check your emails first thing in the morning?
- Are you a zombie without your morning coffee too?
These relatable lines tap into common behaviors, encouraging readers to see how their experiences compare.
2. The “How To” Subject Line
Why it works: Clear and benefit-driven, “How to” subject lines instantly signal value.
Examples:
- How to get better marketing results through beautiful design
- How to win friends and influence people
- How to get 1,000 new email subscribers in 1 day
Tip: Focus on the benefit, not the process.
3. The Scarcity Subject Line
Why it works: Scarcity triggers urgency. People act faster when they fear missing out.
Examples:
- Only 2 days left to get 50% off shoes
- Hurry! Only 3 consultation spots left
- Get free shipping if you order within the next hour
Reminder: Ensure the offer is relevant and valuable to your audience, or urgency won’t matter.
4. The Announcement Subject Line
Why it works: Words like “Introducing” or “New” signal fresh, exclusive content.
Examples:
- Introducing Canvas: A better way to send emails
- Update to our iPhone App
- See our new design gallery
According to studies, “Introducing” boosts open rates by 9.45%, and “New” by 3.26%.
5. The Number-Based Subject Line
Why it works: Numbers provide structure and set expectations, which leads to more opens.
Examples:
- 30 ways to build your email list
- 3 steps to sending beautiful email campaigns
- 10 product announcement emails reviewed for conversion
Pro Tip:
- Use low numbers for quick, easy processes.
- Use high numbers when offering lots of value.
6. The Curiosity Gap Subject Line
Why it works: This formula plays on the psychological need to fill knowledge gaps.
Examples:
- Dave Richardson asked the most basic question—and stumped everyone
- This little-known trick will boost your email click-through rate
- 9 out of 10 Americans are wrong about this fact
Leave just enough out to spark interest, but not so much that it’s vague or spammy.
7. The Surprise Subject Line
Why it works: Humor or the unexpected can stop a reader mid-scroll.
Examples:
- Warning: Unattended items in your cart may be eaten by gnomes
- What Elvis Presley can teach you about email marketing
Even mundane content can get attention if framed in an unusual or playful way.
8. The Personalized Subject Line
Why it works: People respond better when they feel the message is just for them.
Examples:
- John, are you a zombie without your morning coffee too?
- John, 9 out of 10 Americans are wrong about this fact
- John, just 2 days left to get 50% off boots
Stat: Including a subscriber’s name in the subject line increases open rates by 14.68%.
Bonus Tips: How to Write Great Subject Lines Today
- Segment your audience: Don’t send one-size-fits-all subject lines.
- Use personal details: Go beyond names—location or interests work too.
- Be specific and concise: Tell readers exactly what’s inside.
- Use strong, actionable verbs: Lead with action words like Shop, Download, Join, Discover.
- Send at the right time: Align your message with your audience’s mindset and habits.
How Long Should Subject Lines Be?
Aim for under 40 characters for mobile users. Email clients like Gmail often cut off anything longer. Make your point fast and up front.
5 Great Subject Lines to Inspire You
- Stop wasting money on ads—start doing this instead
- Your free eBook is inside (but not for long)
- Just 3 ingredients: dinner in 15 minutes
- How we grew our list by 10,000 subscribers in 30 days
- Ready for a better Monday?
