What Is the Perfect Subject Line Length?

Vladislav Podolyako
Apr 29, 2022
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Email marketing has been around for quite a while, and it is still highly popular among companies and marketers around the world. Given the fact that today there are more than 4 billion email users in the world, it makes pretty good sense for brands to leverage this channel with the purpose to acquire new leads and turn them into actual clients. After all, most people who your business targets are likely to use Gmail or another email provider. So, if you are not investing in email marketing, your brand is missing out on a huge number of potential sales.

Okay, the value of email as a marketing tool is clear. But what is the key to the success of every marketing email that you send? The success is determined by a number of factors, including relevancy, proper targeting, original content, and a powerful call to action. And then there are also the subject lines of your emails that also determine success.

What is an email subject line? Why is it so crucial? And, most importantly, how do you make the most of it? In this article, the Folderly team is going to tell you everything you need to know about writing subject lines that work. Let’s dive in!

Email Subject Line: Definition

Before we can move on to discovering the role of subject lines in your email marketing strategy and identifying the best ways to use them, it is vital that we get clear on the definition first.

In a nutshell, an email subject line is the first thing (after the sender’s name) that your email clients will see when they receive an email from you. Basically, it should indicate the main topic of your message and perform a number of vital tasks.

Why Do Subject Lines Matter So Much?

Given the fact that your recipients will see your email subject lines way before they even open your message, it is not hard to guess that they play a decisive role in the open rates of your marketing emails.

What tasks do they perform?

  • First of all, email subject lines have to grab the recipient’s attention. They have to drive attention and spark curiosity to make the recipient want to open your email.
  • Secondly, an email subject line also has to inform the recipient about your purpose. It should state the reason why you are reaching out to a particular person. Thus, it plays a significant role in attaining your objectives.
  • Lastly, effective lines also help your emails stay away from the recipient’s spam folder. Make them informative, clear, and catchy, and your emails will not fall under the common spam filters.

What Is the Best Email Subject Line Length?

Now that you know what they are and why they matter so much for your campaigns, the next logical question is: How do you make them effective? The answer may surprise you, but the most critical success factor is the length of your email subject lines.

We’ve already told you that a perfect email subject line should be engaging, catchy, and state the purpose of your message. Given that, it can feel like you can write literally anything in your subject line, as long as it meets the stated goals.

But here’s the thing - Gmail, as well as other inbox service providers, limit the character count of subject lines. That is, your clients will only see a certain number of words in a subject line when your message reaches their inbox. Thus, choosing the optimal subject line length is crucial for your success.

For years, there have been lots of debates concerning the length of the perfect subject line. According to research, most lines are between 41 and 50 characters. At the same time, longer subject lines (61-70 characters) tend to have higher open rates (17%).

But is there really a direct correlation between the open rate and your email subject line length? - Research shows no.

After comparing the character or word count of different subject lines and their open rates, experts found that Pearson’s correlation value was -.03. This basically means that the word counts of your subject lines don’t directly correlate with low or high open rates. Still, the email subject line length can’t be completely ignored.

Why? The thing is that different devices have different display capabilities. Namely, for emails opened from a typical desktop inbox, you can expect a recipient to see about 60 characters of your line. However, for emails opened on mobile devices, the count of characters displayed on a screen will drop to just 25-30 characters. Thus, if your target audience is using primarily mobile devices to open emails, you may want to opt for shorter subject lines. Otherwise, there is a risk that mobile users will see your email subject lines truncated.

Key Factors to Consider When Selecting Your Email Subject Line Length

Although we’ve already shared with you the average subject line length, this doesn’t mean that the same length works great for everyone. In order to ensure the success of your email campaign, you need to find the perfect subject line length that will work for you in particular.

To do this, you will have to consider two primary factors:

1. Email Providers Your Prospects Are Using

The first piece of data you want to collect and analyze before defining the best length for your subject lines is the platform your subscribers use most often. Is it Gmail, Apple Mail, Outlook, or anything else? Finding the answer to this question is crucial for the success of your marketing emails. Every platform has its own limits on the number of words or characters they show. So, the platform your subscribers use must be kept in mind when calculating the perfect length of your email subject lines.

2. Devices Your Prospects Are Using

Secondly, the optimal length of your lines should also be calculated based on the type of devices your prospects use the most. As was already mentioned, the number of words or characters a user will see depends directly on the size of the screen they use. In order to ensure the best outcomes of your campaigns, you should carefully analyze your prospects’ data and define whether they use computers or mobile devices to read their emails.

Combining the email providers and devices your subscribers use will enable you to identify the right email subject line length for your marketing campaigns.

4 Best Subject Line Tips From Marketing Experts

Want to make your emails stand out from the crowd? In the list below, we have gathered the top email subject line length tips that your business can start using right now!

Put the Key Information in the First 30 Characters of Your Email Subject Line

As you already know, depending on the type of device every recipient uses to read their emails, they can see between 30 and 60 characters of your subject line. Of course, you can analyze your target audience to see what devices they use most often. But, you can never know for sure which customer will use a desktop or mobile device.

To ensure that everyone sees the most important information from your lines, experts recommend you write it in the first 30 characters. This way, the most important part of your message will never get cut off.

Consider Adding Preheaders Under Your Subject Lines

Often, when you are forced to write a short subject line, it can feel like you are cutting down your main message. If you feel the same way, adding a preheader might be the answer! Basically, a preheader is an additional text placed next to or under your line. It is used to complement and strengthen your subject line.

Don’t Make Your Subject Lines Too Wordy

Trying to deliver a complete and powerful message to your recipients, it can be easy to write subject lines that are too wordy. But, if you tend to do so, remember that the best lines are concise and straight to the point.

Don’t stuff your lines with lots of spammy words. Also, keep the message clear and short. To do this right, try the following exercise - write down the main message you want to deliver, and then try to cut down on the words that don’t deliver any real value. When you finish, your line should only consist of the optimal number of words and, at the same time, deliver your main message.

Always Test

Lastly, one more tip for ensuring the maximum effectiveness of your emails is to always conduct thorough tests. In the following section of our guide, we are going to tell you how to test your subject lines the right way.

How to Test Subject Lines Effectively

Testing your emails before sending them out is a great way to assess their effectiveness and gain actionable insights on how to improve the outcomes of your campaigns. Simply put, it is a way to see what works best for your audience.

But how do you do this right? Basically, the best way to test emails is to set up an AB split test. This method implies taking two variations of subject lines and sending each to 10% of your audience. As a result, you will be able to see which variation is winning and send it to the remaining 80% of your audience.

In addition, such a test can help you analyze the effectiveness of your content, personalization use, CTA, and other elements of your emails. As a result, you will have a chance to boost your open rate by ensuring that your recipients will receive the most powerful version of your message.

The Bottom Line

Did you know that as many as 47% of people decide whether to open each particular email solely based on the subject line it has? This fact alone indicates the huge importance of an effective subject line for the success of your email campaigns.

Luckily, after reading our guide, you have everything you need to compose lines of the perfect length that will never get into the spam folder and will help you drive more sales with ease!

Vladislav Podolyako
Vladislav Podolyako
Founder & CEO
Vlad’s decades of entrepreneurial wisdom and business building experience have allowed him to successfully mentor a diverse group of business owners, entrepreneurs in growing their companies. A recognized expert in the areas of transforming organizational culture and leadership development, B2B Sales, Marketing, spent more than 10 years building technology products, with a background in communication networks and electronic device engineering.

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