Sales email subject lines: 40 examples, and why open rate is the wrong way to pick one

The best sales email subject lines are short, lower case, specific to the person receiving them, and honest about what's inside. That last part gets skipped in most lists. A subject line that gets an email opened and then disappoints does more harm than one that gets ignored, because disappointment is what leads to the spam button.

In practice: two to six words, in lower case, naming something specific to the recipient, like their job opening, their question or their project. Make the subject match the email's first line. And judge subject lines by replies rather than opens, because opens no longer reliably tell you whether a person read anything.

Why is open rate the wrong way to pick a subject line?

Most subject line advice is ranked by open rate, and the trouble is that open rate stopped measuring people some time ago.

Opens are counted with a tiny invisible image in the email: when it loads, the email counts as opened. Apple's Mail Privacy Protection, introduced in 2021, is designed to stop senders seeing whether you've opened an email. As Litmus explains, it does that by preloading the images, tracking pixel included, whether or not anyone reads the message, and Litmus points out that A/B testing subject lines on opens doesn't work as well as a result. Some corporate security filters also open emails and links to scan them. So a message nobody read can still count as opened, and a subject line can "win" a test just because more of its recipients happened to use Apple Mail.

Replies don't have that problem. Setting aside out-of-office messages, a reply is always a person. If you're choosing between subject lines, choose on replies, and accept that you'll need more emails to see a difference.

The four jobs a sales subject line can do

A subject line that works in sales usually does one of four things. Pick one per email; a subject line that tries to do two, like "quick question about your hiring + a free audit", ends up doing neither.

1. Name something that happened to them. A role they posted, a location they opened, something they launched. This is the strongest, because it shows the email was written for them.
2. Use their words. A phrase from a question they asked in public, or from their own website.
3. Name a person or place you share. A mutual contact who genuinely suggested you get in touch, or a community you're both part of. If the contact didn't actually suggest it, don't use their name.
4. Ask a question they can answer from memory. Not "quick question", which in our view has been used so much it now reads as a template, but a real one, like "in-house or outsourced?"

Being specific gets the email opened. Being honest decides what happens next. The subject lines that hurt you are the misleading ones: they win the open and cost you the sender's reputation.

40 cold email subject lines, by type

The brackets are for the specific detail. Everything is in lower case on purpose, because lower case reads like a note from a person and title case reads like a campaign.

Something that happened to them

1. your [role] opening
2. the [city] location
3. after the [product] launch
4. [project] permit timeline
5. your new [page or feature]
6. saw your [event] talk
7. the [job title] hire
8. since the move to [tool]
9. [award or listing], and one question
10. [conference] follow-up (only if you met)

Their words

11. your question on [venue]
12. "[short phrase they used]"
13. the [problem] you posted about
14. [their phrase], a thought
15. about "[phrase from their site]"
16. [their metric] in [month]
17. the [tool] workaround
18. that [topic] thread from [month]

A person or place you share

19. [mutual name] suggested I write
20. via [mutual name]
21. [mutual name] + [problem]
22. intro from [mutual name]
23. also in [community]
24. fellow [association] member

A question they can answer from memory

25. in-house or outsourced?
26. who owns [process]?
27. still doing [task] by hand?
28. [tool] or spreadsheets?
29. [process] before or after [event]?
30. right person for [problem]?
31. is [problem] on this quarter's list?
32. how are you handling [thing]?
33. is [problem] solved already?
34. worth a look before [deadline]?

Sales emails to people who already know you

35. notes from [day] + next steps
36. proposal for [project]
37. the [document] you asked for
38. [project] pricing, v2
39. [day] call: agenda
40. before [decision-maker] sees it

The last six are for deals already under way, where the job is to say what's inside rather than to earn attention. Here are the emails that go with them.

Follow-up email subject lines

Usually the best follow-up subject line is no new subject line at all. Reply in the original thread and the subject becomes "Re:" plus your original subject. That's honest, since it really is a reply, and it brings the context with it.

Only start a new thread when the follow-up is about something new, and then name the new thing:

• new: [the thing that changed]
• [problem], a different angle
• the [resource] I mentioned
• closing the loop on [topic]

The one to avoid is a fake "Re:" on a first message. It's designed to make the reader think they've already replied. It might work once, and it's exactly the kind of thing that gets marked as spam by the people you most wanted to reach. Here are four follow-ups that each bring something new.

Five rules that cover most of it

Keep it to a few words. Phone inboxes only show the start of a subject line, and a lot of cold email is first read on a phone. Two to six words is a sensible target.

Lower case, no theatrics. No exclamation marks, no emoji, no capitals for emphasis. They're the visual signature of a marketing campaign.

Match the first line. The subject is a promise, and the first line is where you keep it. If the subject says "your [role] opening", the first sentence should be about that role. How the email itself is structured matters more than the subject, but a mismatch between the two is a quick route to a spam complaint.

Don't build it around their company name. "[Company] + [your company]" was clever once. Now it's one of the most recognisable merge fields in sales.

Don't worry about spam word lists. Lists of "spam trigger words" are mostly folklore. The requirements the big mailbox providers actually publish, Gmail's for example, are about authentication, spam complaint rates and unsubscribing, not vocabulary. Our deliverability guide covers what matters.

How do you test subject lines when you only send fifty emails a week?

Mostly, you can't, and it's better to know that than to act on noise.

Telling two subject lines apart by replies takes a surprising number of emails. By standard sample-size maths, reliably spotting a subject line that doubles your reply rate, from 5% to 10%, takes roughly four hundred emails for each version. Spotting a smaller improvement, from 5% to 6%, takes thousands. At fifty a week, a "winning" subject line after two weeks is almost always luck.

So at low volume, don't A/B test the subject line. Pick one that follows the rules above, and put the time into the part that does change replies: whether the first line could only have been written to that person. At higher volume, test one change at a time and give each version a few hundred emails before you decide.

When the subject line isn't the problem

If replies are close to zero whatever the subject says, the subject isn't the variable. The list or the opening line is. A new subject line on an email that could have gone to anybody won't change why nobody answers.

If you're landing in spam, no subject line fixes a reputation problem. Check authentication and your complaint rate first.

And if you're writing to people who already know you, they'll open it because of the name in the From line, not the subject. Put the effort into the first sentence instead.