Email Subject Line Generator
Generate high-converting email subject lines with pixel-perfect mobile previews, spam trigger detection, and AI-powered scoring.
Generated Ideas
Enter a topic above to generate optimized subject lines.
About
In the high-stakes environment of email marketing, the subject line is the gatekeeper. Users make split-second decisions to open or archive based on 3 to 5 words. A subject line that performs well on a desktop monitor is often catastrophic on a mobile device, where truncation occurs not just by character count, but by pixel width.
This tool is an industrial-grade generator and validator. It goes beyond simple templates by calculating the exact render width of your text using standard iOS and Android font metrics. It cross-references your copy against a database of 200+ known spam triggers and scores the psychological impact using industry-standard copywriting formulas. Use this to ensure your message hook is visible, compliant, and compelling before you hit send.
Formulas
The visibility score V is calculated based on the Pixel Width Wpx rather than character count. A standard iPhone viewport allows approximately 320 pixels for the subject line.
Reference Data
| Trigger Category | Impact on Deliverability | Examples (High Risk) | Recommended Alternative |
|---|---|---|---|
| Financial Spam | CRITICAL | $$$, Cash, Credit, Income | Revenue, Budget, Earnings |
| Urgency Bait | HIGH | Act Now, Urgent, Do it today | Ending soon, 24h left |
| Exaggerated Claims | HIGH | 100% Free, Guarantee, Risk-free | Complimentary, Promising |
| Direct Marketing | MODERATE | Buy, Order, Click here | Shop, Discover, View |
| General Spam | MODERATE | Winner, Prize, Dear Friend | Invitation, Update |
| Formatting | VARIABLE | ALL CAPS, !!!!, F.R.E.E | Sentence case, Sparse emojis |