A topic that keeps coming up with email marketing is the subject line. I often get asked if there are any specific “rules” to the character length. I would never go as far as to call these “rules” but there are certain target numbers to consider. First off, before getting into those target numbers, what you have to say is WAY more important than counting a certain number of characters. You may find a subject line that works best for a specific promotion to be no more than one or two words. There’s no better way to find out than to test some subject lines to a small percentage of your list and then roll out the winning subject line to the bulk of your list.
There are now many different ways that people read email. Long gone are the days when you only had to worry about “will they read this at work?” or “will they read this at home?”. Those days you had to only figure out if your readers would be viewing your email using their company’s default email program (like Microsoft Outlook, or LOTUS Notes) or via a web-based email tool like AOL, Yahoo, or Hotmail. Nowadays many people are reading their emails on their iPhones and other mobile devices. Because of that, I tend to recommend that the “meat” of your subject line be no longer than 40 characters (including spaces) in length. You can go longer (around 50 characters or so for promotional emails, no longer than 75 for most newsletters) but I would really try to get your main point across in those first 40 characters. In fact, make it less if you can. The iPhone appears to only show the first 37 characters of the subject line. I know that I read a lot of my email on my iPhone these days and the “from line” and “subject line” are very important in my decision to open the message or not.