ChatGPT Prompts for Email Subject Lines: 50+ Formulas That Work
ChatGPT prompts for email subject lines that get opened. Curiosity gaps, benefit-led, and urgency formulas for newsletters, sales emails, and broadcasts.
The Prompt
Act as an email marketing expert who has analyzed open rates across 10M+ emails.
Generate 20 subject lines for the following email:
Email topic: {topic}
Audience: {subscriber type}
Email type: {newsletter / sales / transactional / re-engagement}
One thing the reader gets from this email: {core value}
Tone: {professional / casual / urgent / curious}
Output format — 5 subject lines per category:
Category A — Curiosity gap: create a question or incomplete thought that forces the open
Category B — Benefit-led: lead with what the reader gets
Category C — Specificity: use a number, stat, or timeframe
Category D — Pattern interrupt: say something unexpected or counterintuitive
For each subject line also provide:
- Preview text (40-60 characters, complements the subject line)
- Predicted open rate relative to average: above / at / below industry average and why
Constraints:
- No "You won't believe...", "This is crazy...", "Last chance" unless genuinely urgent
- All must be under 50 characters (mobile preview)
- None can be misleading — subject must match email content
- No all-caps words
Variables to fill in
-
{topic}What the email is about -
{audience}Who is receiving this email -
{core value}The one thing the reader gets from opening -
{tone}The emotional register of the subject line
How to use this prompt
- Pick one from each category to A/B test in your email platform
- Use the preview text suggestions as-is — most marketers leave preview text blank, which is wasted space
- Run this prompt for every broadcast email before scheduling
- Build a swipe file from your highest-performing outputs over time
Preview text is your second subject line
When no preview text is set, email clients pull the first line of your email body — often something like ‘View this email in browser.’ The prompt generates matched preview text for every subject line. Combined, subject + preview should tell a complete mini-story that earns the open.
The curiosity gap category outperforms on mobile
Mobile users spend <2 seconds deciding whether to open an email. A well-crafted curiosity gap (‘The metric that predicted our best month’) creates an itch that the reader can only scratch by opening. Use this category for newsletters where the content value is high.
Specificity beats vague benefits every time
Compare: ‘Ways to grow your email list’ vs. ‘7 tactics that added 1,200 subscribers in 30 days.’ The second is specific, quantified, and time-bound. The prompt’s Category C forces this discipline — always prefer a number over an adjective.
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