Length of the subject line

We analyzed 1,000 email subject lines from today’s top marketers to discover the best length for an email subject line. Here’s what we discovered.

Your email subject line matters. 47% of people open emails based on the subject line alone, according to research done by Business2Community.

Because of this, people ask us about email subject lines often. And one of the most common questions we hear is this: What’s the best length for a subject line?

To find out, AWeber’s team of email experts analyzed 1,000 subject lines from 100 of today’s top marketers. Here’s what we discovered.

What is the average length of a subject line?

On average, the experts’ email subject lines were 44 characters long.

How long is 44 characters? For perspective, the below subject line from theSkimm (a popular daily newsletter) is 43 characters in length.

Best practices for email subject line length

With so many different combinations, how can anyone write a subject line that will stand out?

Let’s get back to our marketing experts: 71.1% of the 1,000 subject lines we analyzed were between 21 and 60 characters. To stand out from everyone else, instead of focusing on length alone, consider other factors that may affect your open rates. 

1. Keep your most important information in the first 30 characters

Over 50% of emails are opened on mobile devices. Most email clients, like Gmail and Yahoo!, stop displaying an email subject line on mobile devices once it reaches between 33 and 43 characters. The exact number varies from one email client to another.

If you have a strong offer, you shouldn’t be forced to limit your email marketing subject line length. To optimize it for mobile readers, put the most important information in the first 30 characters. This way, this message won’t get cut off in the inbox.

2. Use the preheader to enhance your message.

The preheader is the additional text that appears next to or below your subject line in an inbox. Preheaders help compliment your subject line and can be used as that extra piece of text which may otherwise get cut off at the end of a subject line.

3. Don’t be too wordy

Easier said than done. I’m personally someone who rambles on and often uses more words than needed when talking about something.

How do I overcome this when writing subject lines? 

I start by writing everything I want to say in my subject line, then I reduce it by eliminating or replacing certain words.

Here’s an exercise:

Subject line idea: Get up to 50% off Athletic Shoes this Saturday only

This example is 51 characters long. How can I modify this to reduce the subject line?

How about: Up to 50% off Athletic Shoes on Saturday

This exercise reduced my subject line characters to 40.

4. Test your subject lines

Every audience is different. Try short and long subject lines with your subscribers to see what works best for your unique audience.

Set up an AB split test, sending 10% – 20% of the audience the test with the winning variation receiving the remaining 80% – 90%. This way you maximize your open rates by ensuring the strongest subject line gets sent to the majority of your audience.