What to Know When Writing an Email’s Subject Line

Last updated on March 15, 2023 by Cameron Sheppard

As the flowers of spring bloom colors of rainbow wool and the pollen spreads to so many a bucketful, the everlasting influx of emails can make us feel as angry as a bull. Thousands upon thousands make us wonder, “shall mine be opened even once without blunder?”

With my full apologies regarding the poor poetry above, I know it can be a struggle to get your email out there. But the first question to ask yourself is: why should the recipient choose to read this email over all the others? That answer is easy on paper but hard in practice: the email subject line. In this article, I’ll go over the best practices to help yours stand out.

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Three methods of capitalization

A title’s capitalization might have only seemed important when you were drafting essays in English class, but it also plays a part in email subject lines. There are three main methods of capitalization: title case, sentence case, and one that has grown in popularity in recent times: lower case.

Title Case: this is the most common method of capitalization in an email’s subject line. There is no doubt why, though, because it often conveys a sense of professionalism and reliable business. Titles Are Capitalized Like This, where the first letter of each word (except articles and unimportant prepositions) is capitalized.

Sentence Case: when the first letter of a sentence is capitalized, and other words aren’t unless they are proper nouns or acronyms. A study by Inntopia showed sentence case led to more open rates than title case, which makes sense because it’s easier to read in the sea of title case emails.

Lower Case: when the entire sentence goes uncapitalized. This is likely the email you will see first in your inbox but can seem unprofessional. This may be useful for companies that provide design services, but not for those who provide legal services.

Make subject lines go straight to the point

An email subject line can only have so many characters, so it’s important to drive straight to the point. In fact, Mailchimp, an email marketing and automation platform, recommends your subject lines are no more than 60 characters long. This is roughly between 8 to 12 words, depending on each word’s length.

Provide a reason to click

Your recipients have dozens if not hundreds of emails enter their inbox each day, so why should they take the time to read yours? Try to caption what makes your email different and what you’re offering inside. An example of what I mean can be seen in the screenshot below:

Email from support@tidio.net, the support for customer service software provider Tidio. Email subject line reads "Add live chat to camerons.dev with this little code snippet".

The email subject line reads “Add live chat to camerons.dev with this little code snippet”. If I’m scrolling through my inbox and suddenly see this, I now know that I can easily add live chat to my website. Tidio provided a reason for me to open their email.

Use numbers and symbols

Now we’re getting into the juicy stuff. Numbers and symbols such as emojis are one of the biggest things you can use to make your email stand out, and they are quite versatile. Use numbers to offer discounts, akin to what DoorDash does below:

Email from DoorDash, a meal delivery service, with the email subject line "Don't Forget: Save 25% on Your Next Order!"

DoorDash’s email subject line reads “Don’t Forget: Save 25% on Your Next Order!” and undoubtedly sticks out in my crowded inbox. This can be taken a step further, though, by adding emojis, seen in another email from DoorDash below:

Email from Doordash, a meal delivery service, with an email subject line that says "Still here: 25% off deliciousness 😋" and makes use of a face savoring food emoji.

Look at that! DoorDash even reminds me that my discount is “Still here: 25% off deliciousness 😋” if I didn’t get it the first time. Moreover, it makes use of a face savoring food emoji which speaks directly to its food-craving audience, while also standing out.

Use emotional power words

Emotion is another way to get your recipients to click, positive or negative. An article by SmartBlogger states that there are seven types of power words: fear, encouragement, lust, anger, greed, safety, and forbidden. The article also lists over 800 power words that you can use in your writing.

In general, choose power words that correlate with how you want the email to affect your target audience. For example, DoorDash might be inclined to use power words like “juicy” and “mouthwatering” to make its audience crave food.

Maintain a level of readability

With the short few seconds or less that a recipient takes to read your email’s subject line, understandability is a must. This means not using complex words that a 13-year-old wouldn’t know the meaning of, because the average American’s reading level is equivalent to a 7th grader’s.

Also note that the amount of syllables in each word directly affects readability. The human brain reads “go to the beach” way faster than “adventure to a pebble-smothered seashore.”

Let me direct you to a useful tool to estimate readability: the Flesch-Kincaid test and a calculator that uses its formula. The calculator rates the readability of your text from 1 – 100 and estimates the minimum grade level of understanding.

Final thoughts

The art of writing email subject lines can seem daunting to the untrained eye, but with these handy tips you’ll be standing out in no time. Just make sure to keep your target audience in mind, because what entices amateur designers might not entice professional lawyers.

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