Free AI Email Subject Line Generator — 40%+ Open Rates | BrandBone
AI Email Subject Generator

Email Subject Lines That Actually Get Opened

Generate up to 10 AI-crafted subject lines engineered for maximum open rates. Includes A/B test pairs, preview text, and spam-score guidance — ready to use in seconds.

Average email open rate: 21%
AI-optimized subjects average: 40%+
Difference per 1k subscribers: 190 extra opens
A/B test pairs included
Spam-safe output
Preview text generated
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Email Campaign Details
Tell us about your email — more context = higher open rates
Up to 10 subjects
0 / 200 characters
+ Add offer details / sender name / brand voice (optional)
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Analyzing your email campaign…
Reading your audience, goal, and product
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Analyzing
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Psychology
3
Writing
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Ready!
This takes 5–15 seconds · AI is applying open-rate psychology
Subject Lines Ready
Click any subject to copy it
Show full AI output (preview text, A/B notes, recommendations)
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How to Get 40%+ Open Rates
Use these subject lines the right way for maximum results

Start by describing your product, service, or email topic in detail — the more context you give the AI, the more specific and compelling your subject lines will be. Choose the right Email Goal for your campaign (sales, engagement, re-activation) as this shapes the psychological triggers used in the copy. Select your number of subjects and writing style — “Mixed” is recommended as it gives you the widest variety for A/B testing. Once generated, you’ll see each subject line as a clickable card — click any one to instantly copy it to your clipboard. Use “Copy All” to get everything at once. Run at least 2 subject lines as A/B tests in your email platform (Mailchimp, Klaviyo, ConvertKit). After 24 hours, check open rates and declare a winner. Run this generator 2–3 times for each campaign — more variations means better testing and higher peak performance.

📊 Always A/B TestNever send to your full list with one subject. Split 20% of your list, find the winner, then send to the remaining 80%.
✉️ Preview Text MattersThe full output includes preview text suggestions. These show under the subject in inboxes and can increase opens by 10–15%.
⚡ Click to CopyClick any individual subject line card to instantly copy just that one. Or use “Copy All” to copy everything at once.
🔄 Regenerate for MoreRun the generator multiple times. Different outputs every run — more variety = better testing = higher peak open rates.
✓ Copied to clipboard!