Free tool
Free Email Subject Line Generator
Tell the tool what your email is about, who it is for, and the main benefit - then get a varied set of subject lines built from proven formulas, each scored for length and checked for spam words. It runs entirely in your browser.
How it works
Your subject line decides whether your email gets opened or ignored. The best ones use a handful of repeatable patterns: curiosity, a clear benefit, a question, a number or list, personalization, gentle urgency, social proof, and the occasional pattern interrupt. This generator turns your inputs into lines across all of those styles so you always have a strong, varied set to choose from.
How to use it: enter the topic of your email (required), then optionally add your audience and the main benefit, and pick a goal like cold outreach or newsletter. The tool generates subject lines best-first, labels the formula behind each one, shows the character count with a length verdict, and flags any spam-trigger words so you can keep deliverability high.
Length matters: aim for roughly 28 to 50 characters so the full line shows on mobile, where most email is opened. Avoid spam triggers like "free", "act now" and "100%" - the tool highlights them for you. Copy any line with one click, then tweak it to sound like you.
This is the same thinking AutoEmail applies when it drafts replies and outreach: clear, human, deliverable. The difference is that AutoEmail writes the full message in your voice and holds it for your approval before it sends.