The Email Subject Line: The Window to the Soul?

Let’s pretend you’re standing in a bar. It’s buzzing. You look your absolute best. You flick your eyes across the room, over the sea of heads, and they crash into another pair of eyes. Beautiful eyes. There’s a weird “fizz” somewhere in the base of your skull.

Or maybe it’s the pit of your stomach. You’re not sure. But here’s what you are sure about…

You can’t see the person’s Ph.D., their rock-hard abs or their bank balance. You can’t tell if they’re going to love your mom, support your weirdest obsession or care for you when you’re old. You can, however, feel that “fizz.” And what’s going to happen next is this: You’re going to find out more. Somehow. Or die trying.

In modern communication, subject lines are some of the best material we have when it comes to winning the race for attention, or creating that moment of intrigue. They’re not very big relative to the whole — I mean, eyes take up less than 10% of the face — but they do most of the all-important selling for you.

It makes sense, therefore, to optimize them as much as you can, to doll those babies up!

Here’s the problem: everyone has advice about the best, the right, the only methods.

But me? I like to follow the experts when it comes to matters that matter. In my world, email matters almost as much as love does. So I turned to Mailchimp’s 2021 study of 24 billion delivered emails, with subject lines composed of approximately 22,000 distinct words.

To this, I added the advice of other gurus, plus my experience. Here are the highlights:

5 Ways to Create Fizz

1. Length

A typical inbox reveals about 60 characters of an email’s subject line, while a mobile phone shows 25 to 30 characters, says HubSpot — and 46% of emails are opened on mobile devices. Get to the point in six to eight words. My sweet spot is seven.

2. Sufficiency and Specificity

With the optimal range being six to eight words, try to use them all. Now and then a one-word subject line can be powerful (think “Gobsmacked,” not “Meeting”), but in general aim for scope and detail like this:

  • Requesting Project X idea submissions — due 15 Jan
  • An introduction: Nelly P, please meet Daniel J
  • Potential collaboration on radio commercial copy
  • John, see how you compare with your competitors

Vague subject lines (e.g., “Have a second?”) will make your reader delete faster. Try this:

  1. Focus on one call-to-action (e.g., “Register”)
  2. Offer a single takeaway (e.g., “Proven tips”)
  3. Indicate how the reader can make use of information (e.g., “Get better leads”)
  4. Specify how your value will be delivered (e.g., “Complimentary webinar”)

And then add relevant detail to get to eight words.

3. Front-Loading

Since you don’t know how much of the subject line will be viewable from the reader’s device, it pays to put the most important information at the start, or compelling details may be chopped off. Look at these examples:


  • Attached is your GDPR Compliance Toolkit

Not meh:

  • GDPR Compliance Toolkit attached. Start now.

You don’t have to tell the whole ugly truth in your subject lines. But it’s best to tell most of it. (Or at least, Simon Leviev, not to blatantly lie. Because then you’re a bad person.)

4. Name-Dropping

As in the world of romantic interaction, there are three types of name-droppers:

  1. The smooth operator who drops your name all over their sentences, making you feel seen, heard and special
  2. The social butterfly who drops other people’s names into your conversations, to build rapport with you based on shared connections
  3. The slimy show-off who flings famous names around the room, often loudly, to seem important and “in the know”

In email, I’d suggest you go with No. 1 and No. 2, like so:

The Reader’s Name

Most email marketing platforms allow you to include first and last names in campaign subjects or bodies, provided that the subjects have supplied these.

And happily, Mailchimp’s (and others’) analysis has found that personalized subject lines do increase open rates, provided that the emails actually contain highly personalized content.

Someone Else’s Name

If you’ve been referred to the reader by a mutual acquaintance, don’t save that handy little nugget for the body of the email. Put the person’s full name in the subject line, to grab the reader’s attention and establish early credibility:

  • Referred to you by Tiffany M: pitch opportunity

A quick word on common ground: In the subject lines of follow-up emails, be sure to reference a past meeting or conversation to help your recipient to remember who you are:

  • Met at Starbucks yesterday; media release attached

5. Punctuating

As a writer, I have strong opinions about punctuation marks. (I can hold forth for hours on the Oxford comma, which I adore — but not all editors adhere to. I have a mutually respectful, if complex, relationship with the semicolon. And incomplete or duplicated ellipses makes me incandescent with rage.)

There are three interesting punctuation tricks for email subject lines.

Trick 1: Research says it’s best to use no more than three punctuation marks per subject line. Too many can make your email look like spam, especially if you include special characters. I tend to use one or, at most, two.

Trick 2: As you might expect, the use of an ENTIRELY CAPITALIZED SUBJECT LINE yields lower open rates than a sentence case one. Because it’s shouting! But surprise, surprise … title case, where “The First Letter of Each Main Word Is Capitalized,” works better than sentence case, “Where the first word starts with a capital letter.” This hurts my grammar-purist soul, so I don’t use it myself, but you can.

Trick 3: Worldata indicates that using brackets (parentheses) in your subject line can boost open rates by 31%. They draw the eye, subconsciously, to whatever’s inside. And that small detail can be enough to entice the reader to open the email. Some examples are:

  • Welcome back to the platform, Tiffany. (We missed you.)
  • We’ll match your donation. (Today only!)
  • Writing well is hard. We can help. [FREE VIDEO]

Let me be clear: Dating can (and often does) lead to incredible things. But it can also be complex, just like email. It makes sense, therefore, to nail the first impression — if for no other reason than doing so is extremely good practice for “The Big One.”

Tiffany Markman is an international speaker, trainer and writer, known for her work on communication, messaging, marketing and more. She’s collaborated with over 450 brands worldwide — both big and small — over the last 17 years, encountering writing that ranges from the sublime to the absurd. She’s also delivered keynote addresses, created masterclasses and presented training in 14 countries. Markman likes her coffee strong and black, her paragraphing short and tight and her apostrophes in all the right places.