Cold email subject lines: 25 examples grouped by why you are writing

• It comes from the reason you are writing. If you have one, such as a new team, a launch or something they wrote, the subject line names it. If you cannot name one, the problem is the email, not the subject line.
• It could only go to this person. Swap in another company's name. If the line still works, it is generic.
• It says what the email is about. The recipient decides from the subject whether to open, archive or report the message. In the US, the Federal Trade Commission's CAN-SPAM guide says the subject line “must accurately reflect the content of the message.”
• It reads like a note from a colleague. Plain words in sentence case, without exclamation marks, capitals for emphasis or emojis you would not send a colleague.
• The first line picks up where it stops. A subject about a launch should open on the launch, not on who you are.

Each table pairs a subject line with the first line of the email it introduces, so you can see how the two connect. All the details are fictional.

A new hire or a new team

Use these when a role, a team or a leader is new and your offer helps with what they are setting up. Check the date: a hire from last year is not news.

A launch or a product change

Use these when the company has shipped something that creates work your offer helps with. Name the launch the way the company names it.

Growth, funding or expansion

Use these when growth changes what the team has to do. Write about the consequence you can help with, not about the money raised.

Something they wrote or said

Use these when the person has said something in public that connects to your offer. Refer to what they actually said, and do not stretch it into agreement with you.

A referral or a shared connection

Only use these when the connection is real, and say exactly what the other person said. A pointer to the right team is not a recommendation.

An event

Use these when you were both at an event, or the company is about to be at one. If you did not speak, do not imply you did.

A plain question

Use these when you have no event to point to but a real, narrow question about who does what. The email should then ask exactly that question.

• “Re:” or “Fwd:” on a first email. They claim a conversation that never happened, so the subject line misstates what the email is. Use “Re:” only when you are replying in a real thread.
• Invented familiarity. “Following up on our call” or “As promised” when there was no call and no promise.
• False urgency. “Urgent”, “Final notice” or “Last chance” when nothing is urgent.
• A question the email never asks. “Quick question” is fine when the email is one short question, and misleading when it opens a pitch.
• A name as the only personal detail. “Maya, an idea for you” shows you have a list, not a reason.
• Broken merge fields. “{Company} + us” or an empty first name. Send yourself a test before any sequence starts.
• Capitals, exclamation marks and symbols. They make a note look like an advertisement.

Short enough to read in full in a phone's inbox, where long subject lines are cut off. How much fits depends on the phone and the mail app, so there is no single character count to aim for. Send the email to yourself and look at it in your own inbox on your phone.

Put the specific words first, so they survive if the line is cut: “Northstar Pay launch: support volume” keeps its point, while “A quick thought about support after your launch” loses it.

• Don't judge by opens. Apple says Mail Privacy Protection “prevents senders from seeing if you've opened the email message they sent you.” Open tracking cannot tell you whether those recipients read the email.
• Count replies, and the replies that lead somewhere. A reply that says “wrong person” is useful, but it is not a result.
• Change one thing at a time. Keep the audience, the first line and the timing the same, and change only the subject line.
• Be wary of small sends. On a few dozen emails, a couple of replies either way is not a difference you can act on. Keep testing before you call a winner.
• Keep a record. Write down each subject line, its first line, who received it and what came back, so the next test starts from evidence.

A follow-up to an unanswered email usually belongs in the same thread, so the subject line stays the same and your email app adds “Re:”. When you start a new thread, name what the new message adds. Our follow-up guide lists a subject line for each of its 12 follow-up templates.

Write the subject line last, after the first line, from the same fact. If you use an AI service to draft, give it the verified reason and the email, and ask it to stay inside them:

Write three subject lines for the email below. Each must name the verified reason for writing and nothing else, in plain words, short enough to read in full on a phone. Do not use “Re:”, “Fwd:”, questions the email does not ask, urgency or the recipient's name. Flag any subject line that states something the email does not support.

Check the result against the source. A fluent subject line can still overstate what the prospect said or did. Our B2B buying signals guide explains how to tell a real reason to write from a coincidence.

Buena drafts each first email from a sourced reason to reach out, so the subject line and the first line come from the same evidence. Every personal line shows the source it came from, and sending needs your approval.

The subject-line rule is quoted from the Federal Trade Commission's CAN-SPAM Act compliance guide, and the description of Mail Privacy Protection from Apple's iPhone User Guide. Both were checked on October 1, 2026. This page is not legal advice; apply the rules that govern your own channels and markets.