Cold email
The subject line of a cold email.
It is read on a phone, between two meetings, next to sixty others. You have five to seven words.
In short
A good cold subject line is short (five to seven words), descriptive rather than promotional, and contains something specific to the recipient: their company name, their trade, or an observation about them. It should look like a message written by one human to another, never like an advertising hook.
What gets opened
Three forms work repeatedly. The recipient's company name paired with a concrete subject. A direct, short question about a problem in their trade. And a reference to something verifiable: a hire, an opening, a publication.
What those three have in common: they promise nothing. A subject line promising a quantified result is filed as advertising immediately, including when the promise is true.
Works
« Question about your quotes », « [Company] and client follow-up », « Saw your job advert ».
Does not
« Boost your sales », « An exceptional offer », « Don't miss this opportunity ».
Never
Capitals, exclamation marks, the words free, deal, urgent, and anything resembling an automated reminder.
Personalisation creates a debt
Putting the company name in the subject noticeably lifts opens. But a personalised subject followed by a generic body produces exactly the opposite of what you wanted: the reader feels handled, and they are right.
The rule is simple: only personalise the subject if the body is personalised to the same degree. Otherwise stay with something neutral and descriptive that promises nothing it will not deliver.
What does not belong there
Your company name has no place in the subject of a first message: your reader does not know it, it means nothing to them, and it eats two of your seven words.
The word « partnership » has become a cold-outreach signal on its own. « Commercial proposal » announces a read to be postponed, which means never.
Frequently asked questions
Should you use a question mark?
A genuine question in the subject works well, provided the message answers it. A rhetorical one is spotted immediately and costs more than it returns.
Does lowercase look more authentic?
It mimics a message dashed off between colleagues and sometimes lifts opens, but it jars in formal sectors. Test it on your target rather than applying it as a principle.
Can you reuse the subject when following up?
Replying in the same thread keeps the original subject and recalls the earlier exchange, which works well for the first two follow-ups. Beyond that, change both subject and angle.
Keep track of every follow-up
Lea CRM keeps your contacts, deals and reminders in one place, and shows you every morning what needs doing today.