Subject Line Length Test

The subject line is the first thing your subscribers notice about your mailing, and it is an important element that helps determine whether or not they will open the mailing. Because you don't want to lose readers to an overly-complicated subject line, Informz provides a feature that will tell you when your subject line is getting too long!


Navigate to Mailings > View.

Identify a mailing and hover over the corresponding hover menu icon. Click Edit.

Scroll to the Envelope section of the Set-Up tab.

Click Edit next to the subject line field (alternatively, click directly in the subject field).

Enter the subject line text.

Directly underneath the subject line, there are indicators that will update based on the character length.


There are two subject line indicators: one for mobile readers and one for desktop readers. Informz lets you know if the subject line is OK, Fair, or Poor based on the subject line length.

The mobile indicator updates faster than the desktop indicator.

The desktop indicator will only read as "poor" when the subject line is long (about 50+ characters).

Just a Pinch of Salt...

The subject line length indicator is an awesome feature, but one that you should take "with a grain of salt." Remember, it is only a guideline. You know your subscribers best, and if you feel that you need a subject line that pushes the indicators out to "poor," that is okay! Informz will not stop you from sending! The purpose of this feature is simply to let you know when your subject line is not at an optimal reading length.

(Hint: Try doing some A/B Testing of your subject lines to really know what your readers are more responsive to.)