AI Email Subject Line Generator
This free AI email subject line generator writes ten subject lines for your email, tuned to the type you send: promotion, newsletter, announcement, reminder or cold outreach. Each aims to stay under 60 characters so it is not cut off on a phone. A length table marks any line that is too long.
AI Email Subject Line Generator
AI Writing
About this tool
The generator asks Claude, an AI model, for ten varied subject lines: some direct, some curious, some benefit-led. It avoids spam trigger habits such as all capitals, repeated exclamation marks and fake urgency, which can hurt deliverability and trust.
Describe what the email is about, choose the email type and run it. The lines are listed in the copy box and in a table with their lengths. Pick two or three and A/B test them in your email tool, because only your own audience can tell you which one wins. The result is a draft to refine, so run it more than once if the first version is not quite right.
The brief takes up to 600 characters. The AI cannot count characters exactly, so use the table. Subject lines are AI-generated, so make sure the subject matches the email content, since misleading subjects cause unsubscribes and spam reports. Follow the email laws that apply to you, including consent and unsubscribe rules.
Frequently asked questions
How long should an email subject line be?
Keep subject lines to about 40 to 60 characters so most of them show on a phone. Put the key word first in case the end is cut off. The table in the results shows the length of every line and flags those over 60.
Will these avoid the spam folder?
The tool avoids common spam habits, but deliverability depends on your sender reputation, list quality and content, not only the subject. Do not use misleading subjects, fake "Re:" prefixes or heavy punctuation, and always include an unsubscribe link.
How much text can I use, and are there limits?
Each run accepts up to 600 characters for the email brief. There is also a fair-use limit on AI runs per visitor each day so the tool stays free. When you reach it, the free tools that do not use AI still work, and you can run this one again the next day.
How accurate is the AI output?
No AI output is guaranteed accurate. This tool can misread your meaning, repeat a common phrase or state a detail you did not give it, so read the subject lines through, check every name, number and claim, and edit it before you publish. Treat it as a fast first draft that you review, not finished copy.