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Subject Line Length: Test for Results

Subject line best practices tend to be all over the map.  We’ve seen studies claiming the shorter subject line is better, and others saying longer subject lines are. And we’ve seen studies saying personalization works and other saying it doesn’t. On subject lines, don’t assume you know the best length. Instead, test, test, test.

What’s an email marketer to believe?

When it comes to subject lines, the only email marketing best practices you can really depend on are the ones you determine yourself through testing.

Consider just subject line length, for example. As email consultants, we still run into the mindset that there’s a hard and fast rule one must adhere to. Email marketers can get fixated on the 35-character limit but that’s not necessarily true. There is no hard and fast rule, only your rule.

A short subject line might work best for you. A long subject line might work best for you. Or something in between might be just the right length. There’s only one way to know: Try A/B testing for your initial answers. Then continue to test and refine.

Don’t automatically dismiss longer lines. Consider the benefits of the longer subject line. A long subject line tells the recipient more about what to expect from the email content, possibly leading to more opens. For example, a magazine touting their newest issue might reference three articles in the subject line.

On the other hand, short subject lines can be “long enough” to get opens when the emails are known to be relevant to the recipient, expected and timely. If you’ve built up a rapport with your audience, the shorter subject line might be the way to go.

And that’s another reason for continuing to test. It could be you’ll need longer subject lines until your audience gets engaged, then shorter subject lines will suffice. Or it could be for some kinds of content your subject lines will perform better shorter and other kinds of content will perform better with longer.

The key is not to take any advice for granted. Instead, test for results…the best results for you.

Published On: May 4th, 2012Categories: Email marketing best practicesTags: ,

About the Author: Sharon

Sharon Ernst from is on a mission to improve the business and marketing writing skills of today’s workforce with her blog, newsletter and online classes. Her newest class on intermediate email copywriting covers 19 tips and techniques non-copywriters can put to use right away for better results. The class has real-life examples and before/after comparisons to make the lessons stick. Find her class at When she’s not busy helping employees, managers and marketers master their writing skills, she and her husband are busy raising pigs, cows, chickens and vegetables on their 20-acre farm.

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