What's the Ideal Subject Length for an Email Campaign?

Not sure if your email is ever going to be read because your subject is too long (or too short)? While we can’t write the email for you, we can help you make sure that it’s at least the correct length.

The length of an email subject line is of paramount importance in the realm of digital communication. It serves as the initial point of contact and is often the deciding factor determining whether a recipient opens the email or sends it straight to the trash. A subject line is like a headline for a news article: it needs to capture attention, convey the essence of the content, and provoke curiosity—all within a confined space. With the rise of mobile device usage, this becomes even more crucial, as subject lines that are too lengthy might get truncated, causing potential readers to miss out on the crux of the message.

Moreover, the importance of a well-crafted subject line goes beyond just the open rate. It’s a reflection of the brand’s voice, professionalism, and relevance to the recipient. In a digital age flooded with countless emails, spam messages, and notifications, users have become discerning about which emails are worth their time. An appropriately sized subject line can make the difference between being perceived as spam or a genuine message. Research has shown varying optimal lengths for subject lines, but the key is to remain concise while effectively conveying the purpose and value of the email. Balancing brevity with impact ensures that the email not only gets opened but also resonates with its intended audience.

How To Find The Ideal Subject Length


Input Your Potential Subject

Navigate to the "Enter Email Subject" section. In the provided text area, type or paste the email subject you wish to evaluate. The spacious text area allows you to comfortably view and edit your subject.



Once you've entered your desired subject, click the "Evaluate" button below the text area. The tool will immediately calculate and display two pieces of vital information: the total character count of your subject and a grade based on the subject's word length.


Review and Refine

Below the text area, you'll find the results of your evaluation. The "Character Count" tells you how many characters, including spaces, are in your subject. This helps ensure your subject won't get cut off on various devices, especially mobile. The "Grade" offers feedback based on the number of words in your subject, with seven words being the optimal length. Use this feedback to refine and optimize your email subject, ensuring it has the best possible chance of catching your audience's attention.

Find The Perfect Email Subject

Enter Email Subject

Character Count: 0

Grade: N/A

How Has The Subject Length Changed Over Time?

In the nascent days of electronic mail, the virtual landscape was markedly different from today. Internet speeds were slow, screen resolutions were low, and desktops dominated the scene. Email was a novel concept, and the few who engaged with it had the patience to deal with its quirks. Back then, the length of an email subject wasn’t much of a focal point. Instead, clarity took precedence. Lengthy subjects, providing as much context as possible, were not uncommon. After all, email was a substitute for formal letters, and verbosity was a mark of professionalism.

However, as the turn of the millennium approached, there was a paradigm shift. The burgeoning popularity of email transformed it from a professional communication tool into an everyday necessity. Consequently, inboxes started overflowing, spam emails emerged, and the attention span of users dwindled. Marketers and communicators began realizing the importance of being succinct. By the 2000s, the mantra had shifted to brevity, with the ideal email subject length hovering around 50 characters. The rationale was straightforward: if the subject was too long, the critical message could get truncated, especially with the varying display capabilities of different email clients.

Enter the smartphone era, and the game changed once again. With mobile devices becoming the primary means of checking email, screen real estate shrunk drastically. Suddenly, having an email subject that was easily scannable and immediately captivating became paramount. The new sweet spot veered closer to 30-40 characters. But it wasn’t just about character count anymore; every word had to pack a punch. The success of an email campaign began to hinge significantly on the efficacy of those few words in the subject line.


Looking ahead, as we move further into the age of smart devices and wearables, the ideal email subject length is poised for more evolution. Wearables, with their even smaller screens, may necessitate even sharper conciseness. On the flip side, the integration of voice assistants might bring back the era of longer, descriptive subjects, as users might prefer to hear a more detailed preview before deciding to open an email.

Moreover, the rise of AI and machine learning suggests that future email systems might be smart enough to tailor subject display based on user preferences and device type. An AI could potentially craft or adjust the subject length in real-time, optimizing it for the user’s current device or attention span.

All of this is a reason to understand that best practices, at least when it comes to email subject lines are likely to change in the future just as they have done in the past. And, while this is self serving, is all the more reason why you should bookmark this page.