Email Subject Line Generator
Generate compelling, high-open-rate email subject lines that drive engagement. Get AI-powered suggestions with predicted performance scores.
Describe Your Email
Tell us about your email campaign to generate tailored subject lines
What Makes a Great Email Subject Line?
Your subject line is the gatekeeper to your email content. With the average person receiving 121 emails per day, you have just seconds to capture attention. Our AI analyzes:
No Subject Lines Yet
Enter your email topic and click "Generate" to create subject lines
Your AI-generated email subject lines will appear here
Subject Line Length Guide
The Psychology of High-Converting Email Subject Lines
47% of email recipients open emails based on the subject line alone. Your subject line is the single most important factor in determining whether your email gets opened or ignored. Mastering subject line psychology can dramatically improve your email marketing performance.
Open based on subject line
Mark as spam based on subject
Avg. email open rate
Essential Elements of High-Opening Subject Lines
Keep It Short and Mobile-Friendly
With 46% of emails opened on mobile devices, keep subject lines under 50 characters. Mobile preview cuts off longer subjects, losing impact and clarity.
Create Curiosity Gaps
Tease valuable information without giving everything away. Questions, incomplete statements, and mysterious phrases compel readers to click to learn more.
Use Personalization
Personalized subject lines are 26% more likely to be opened. Include the recipient's name, location, or previous behavior when possible.
Leverage FOMO and Urgency
Time-sensitive offers and scarcity create fear of missing out. Words like "today," "limited," "ending soon," and "last chance" drive immediate action.
Proven Subject Line Formulas by Email Type
Different email types require different approaches. Use these proven formulas for maximum impact:
Newsletter Formula
[Number] [Topic] insights you need this weekExample: "5 marketing insights you need this week"
Promotional Formula
[Discount]% off [Product] - [Time Limit]Example: "50% off all courses - ends midnight"
Re-engagement Formula
We miss you, [Name]! Here's [Incentive]Example: "We miss you, Sarah! Here's 20% off your return"
Curiosity Formula
You won't believe what [Something Surprising]Example: "You won't believe what happened at our office today"
Question Formula
Are you making these [Number] [Mistake Type] mistakes?Example: "Are you making these 3 email marketing mistakes?"
Benefit Formula
How to [Achieve Desired Result] in [Timeframe]Example: "How to double your conversions in 30 days"
A/B Testing Best Practices
Never send an email campaign without testing your subject lines. A/B testing can improve open rates by 30% or more.
What to Test
- Length (short vs. long)
- Tone (formal vs. casual)
- Personalization (name vs. no name)
- Emojis (with vs. without)
- Numbers vs. words
- Questions vs. statements
Testing Guidelines
- Test one variable at a time
- Use statistically significant sample sizes
- Send tests at the same time
- Wait for full results before deciding
- Document what works for your audience
- Retest periodically - preferences change
Words and Phrases to Avoid
Certain words and phrases can trigger spam filters or reduce open rates. Avoid these red flags:
Spam Trigger Words
Overused Phrases
Note: Context matters. Some "spam words" can work if used authentically and sparingly. Always test with your specific audience.
Frequently Asked Questions
What's the ideal email subject line length?▼
41-50 characters is optimal for mobile devices. With 46% of emails opened on mobile, this length ensures your entire subject line is visible in the preview. Desktop email clients can display up to 60 characters, but prioritize mobile users. Our tool shows character counts and warns when you exceed mobile-friendly limits.
Should I use emojis in email subject lines?▼
Use emojis strategically, not excessively. Emojis can increase open rates by 56% when used appropriately, but overuse looks spammy. Best practices: Use one emoji maximum, place it at the start or end, ensure it's relevant to your content, and A/B test with your specific audience. B2B audiences typically respond less favorably to emojis than B2C.
How can I improve my email open rates?▼
Focus on relevance, timing, and sender reputation. Beyond subject lines, open rates depend on: sending from a recognizable sender name, emailing at optimal times (Tuesday-Thursday, 10am-11am works best for most), segmenting your list for personalized content, maintaining a clean email list, and consistently delivering value. A great subject line on a poorly-timed email to an irrelevant audience won't perform well.
What's a good email open rate?▼
21-23% is the average across all industries. However, this varies significantly by industry, audience, and email type. B2B averages 15-25%, while B2C can reach 20-30%. Educational content often achieves 25-35%. Newsletter open rates of 30%+ are excellent. Transactional emails can exceed 80%. Focus on improving your own baseline rather than comparing to general benchmarks.
How do I avoid spam filters?▼
Avoid spam trigger words, excessive punctuation, and ALL CAPS. Don't use multiple exclamation marks!!!, avoid words like "free," "guaranteed," "no obligation," don't write in all capitals, use a verified sender domain with proper authentication (SPF, DKIM, DMARC), maintain a healthy sender reputation by avoiding complaints and bounces, and always include an unsubscribe link.
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