Free Newsletter Subject Line Generator
Get 5 newsletter subject lines that lift open rates. Paste your newsletter content or describe the issue — the AI writes subjects optimized for Substack, Beehiiv, ConvertKit, and Mailchimp.
30+ newsletter subject lines that work
Proven newsletter subject line patterns from high-performing B2B and creator newsletters. Organized by angle — mix and match for your next issue.
Curiosity-led
- What we got wrong about [topic]
- The email I almost didn't send
- One chart changed our mind
- Nobody is talking about this
- Why [trend] is actually backwards
List / roundup
- 5 links worth your time
- 3 things I'm watching this week
- This week in [niche]
- 10 tools we tested so you don't have to
- Weekend reads: [topic]
Direct value
- A free template for [task]
- Our [guide/framework] is inside
- Here's the exact [thing] we used
- The [thing] checklist you've been asking for
- Bookmark this for [use case]
Opinion / hot take
- Hot take: [opinion]
- I was wrong about [topic]
- An unpopular opinion on [subject]
- Why everyone is doing [thing] wrong
- [Industry] won't want you to read this
Behind-the-scenes
- Inside our [process/decision]
- How we shipped [project] in [timeframe]
- The metric we actually care about
- What this week taught us
- Transparent update on [topic]
Story-driven
- The day I [memorable event]
- This made me rethink [topic]
- A story about [experience]
- I finally understood [concept] when…
- The conversation that changed our approach
Newsletter subject line best practices
Write the subject after the newsletter
Most people write the subject line first. Flip that. Write your newsletter, then pull 3 subject line candidates from the most interesting parts. The best subjects surface the one thing that's genuinely interesting in the issue.
Pair subject + preview text
Preview text gets almost as much real estate as the subject line itself. Use it to complete a thought the subject starts. Subject: "We messed up last quarter." Preview: "Here's exactly what happened and what we're changing."
Consistency matters for recurring newsletters
If you send weekly, some subscribers learn to recognize your pattern ("Issue #47" style). Others respond better to issue-specific subjects. Test both. Track opens by subscriber cohort — new subscribers often behave differently than long-tenured ones.
Don't overpromise
Misleading subjects inflate opens in the short term and destroy list health long-term. One or two clickbait subjects will drive unsubscribes and spam complaints.
Need more than a free tool?
Like newsletter subject line generator? The Aeralis Gmail add-on does this and more, right inside your inbox.
Free tier includes 15 emails/month. No credit card required.
Frequently Asked Questions
Common questions about our newsletter subject line generator
What is a good open rate for newsletters in 2026?
Good newsletter open rates vary by niche. B2B SaaS newsletters: 25–35%. Consumer/lifestyle: 35–50%. Paid newsletters (Substack, Beehiiv): 40–60%. Anything below 20% usually indicates deliverability issues or a subject line problem.
How long should a newsletter subject line be?
Newsletter subject lines work best between 30–60 characters. Too short looks vague ("New post"); too long gets truncated on mobile. The sweet spot: 40–50 characters — enough to communicate value, short enough to fit on most inbox previews.
Should newsletter subject lines use emojis?
Moderate emoji use can lift opens by 5–10% in consumer newsletters (lifestyle, food, entertainment). In B2B or professional newsletters, emojis often hurt. Test with your audience. Never use more than one emoji.
Does the preview text matter?
Yes, enormously. Preview text (the snippet shown after the subject line) is a second subject line. Write it deliberately — don't let it auto-pull from your header. Together, subject + preview should give the full pitch for opening.
Should I personalize newsletter subject lines?
First-name personalization lifts newsletter opens by 10–22% depending on the audience. But only use it if your list data is clean. Fallback behavior ("Hey {firstName}" showing as "Hey ") kills trust.
What day/time gets the best newsletter open rates?
Tuesday and Wednesday 9–11am local time consistently perform best across most industries (Mailchimp, ConvertKit benchmarks). But the real answer is: test your own list. Audience behavior varies.
Is this newsletter subject line generator really free?
Yes, completely free. Generate up to 10 sets of 5 subject lines per hour, no signup, no credit card. Works for any newsletter platform: Substack, Beehiiv, ConvertKit, Mailchimp, Ghost.
See also: general subject line generator · cold email version
More Free Email Tools
Other free tools you might find useful