Cold email subject lines that get opened.
Tell us what you are pitching and who you are pitching. You get a batch of short, human subject lines, each graded, ready to drop into your campaign.
Your pitch
Blank name or company fields become merge tags, exactly as you would send them from HotHawk.
Generated lines
- Fill in your pitch and hit generate.
Grade a subject line you already wrote
Paste one in and we will score it on length, spam risk and personalisation, then tell you what to fix.
What makes a cold email subject line work
A cold subject line has one job: earn the open without looking like a broadcast. The lines that do it are short, specific and quiet. Three to seven words, under 50 characters, no exclamation marks, no ALL CAPS, no "free" or "act now". They read like something a colleague would actually send, because that is the bar an unknown sender has to clear in a busy inbox.
The generator above leans on the patterns that hold up in real outbound: a genuine question, a named trigger, a company reference, a low-key nudge. It grades each one so you are not guessing. But a great subject line only matters if the email gets through in the first place, and that is a deliverability problem, not a copy problem.
The subject line is the last 5%, not the first
Teams obsess over the subject and ignore the plumbing. It should be the other way round. If your domain is not authenticated, your mailboxes are not warmed, or you are firing thousands of emails from a single inbox, no subject line saves you. HotHawk handles the part underneath: inbox rotation across many warmed Google and Microsoft mailboxes, warmup on real inboxes, and the sending volume to run 40,000 emails a day and more without torching your reputation.
Write the subject here. Send it from infrastructure that gives it a chance.
No credit card required.
Frequently asked
What makes a good cold email subject line?
Short, specific and human. The best cold email subject lines run three to seven words, read like a line one colleague would send another, and name something real about the reader or their company. Avoid salesy trigger words, ALL CAPS and exclamation marks, which push you toward the spam folder before anyone reads a word.
How long should a cold email subject line be?
Aim for under 50 characters, or roughly three to seven words. Most inboxes are read on a phone, where a long subject line gets cut off. A tight subject line also looks less like a broadcast and more like a personal note, which is what earns the open on cold outreach.
Should I use the recipient’s name in the subject line?
Personalisation helps when it is real, not when it is bolted on. Using a first name or company name works if the rest of the line is relevant too. A merge tag stuffed into a generic line reads as a mass send. This tool shows both versions so you can see the difference.
Do subject lines affect deliverability?
They can. Spammy words, heavy punctuation and ALL CAPS are signals filters weigh, and a subject that gets no replies over time tells the provider your mail is unwanted. Subject lines are one input though. Reaching the inbox at all comes down to authenticated domains, warmed mailboxes and sensible sending volume, which is what HotHawk handles underneath the copy.
Is this subject line generator free?
Yes, completely free and no signup. Everything runs in your browser, so nothing you type is sent anywhere. Generate as many as you like, grade your own, and copy the ones you want into your campaign.
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Updated 12 July 2026