They are often cut off beyond a certain character length

[nishat@264]

Short titles for your email subject lines
Another tactic you can use to boost your cold email subject lines is to simply make them short… no, really: that’s it. Sometimes, less is more, and that’s often the case when it comes to email subject lines.

An email subject line – warm or cold – that is too long will not attract your target’s attention. This is mainly due to two reasons:

They are long and not very focused.
On the other hand, shorter subject lines are specific and focus on a particular point or goal. Plus, they never get cut off, which is a huge plus.

So, what is the ideal length? After all, it’s a rather wuhan cell phone number list vague term: what’s too long, too short, or just right? In fact, there’s no exact number; all subject lines are different: they promote a single email on a specific topic.

Too long is all that gets cut off. What's the point if it's not seen? A message that's too short is a message that doesn't convey the message you wanted to convey. Why send an email if you don't tell them what it's about?

For what it's worth, there was a study done on email subject line length and open rates . Here are the results:

0-5 words = 16% open rate
6-10 words = 21% open rate
11-15 words = 14% open rate
16-20 words = 12% open rate
21-25 words = 9% open rate
6-10 words is best; I wouldn’t rely on it too much, though. As we said before, every email is unique and needs a unique subject line. 0-15 words pretty much covers it, but make sure the subject line isn’t cut off. Send a message to yourself to check it out.

NOTE: It’s also important to consider that character length, not just word length, is important. This determines how long a subject line appears visually in an inbox, and whether it gets cut off. Screen size and browser zoom can affect this.