Writing a High Impact Email Subject Line

By the Wheelhouse Editorial Team

How many of us have sent an email and forgot to include a subject line? It’s all too easy to focus on the content of an email, and forget all about the importance of the subject line. But your subject line can make or break whether you email gets read at all. Whether you’re sending bulk email campaigns to a large audience, or one-to-one communications to a sales prospect, here are some rules of the road for writing impactful email subject lines.

The Key Objective of Your Subject Line: Open the Email. That’s It.

To write a good subject line, as with any other marketing campaign or sales communication – it’s essential to start with your objective in mind. And in most cases – the objective is simple: you want your recipient to open the email itself. It’s important to distinguish between the objective of your subject line and the objective of your email – these are two different things. Of course, you want your subject line to be relevant to the content of the email, but the subject line has its own job to do – and that’s to make sure the email gets opened so it can be read.

Subject Line Basics: 50 Characters or 10 Words Max

Before we go into details on the content of email subject lines, let’s consider the parameters we have to work with. And those parameters are: you do not have a lot of space. You need to say what you need to say in one short line. The rule of thumb these days is no more than 50 characters or 10 words in your subject line. Five words is even better than 10 words – in fact, the shorter the better.

If you take a look at your email inbox, note which email subject lines stand out amidst the crowd. Often, the short subject lines will stick out simply because so many of the other emails have long subject lines!

The Internet has introduced us to a wonderful amount of information and content, but there’s a dark side to this story - and that’s information overload. Saying what you need to say in the simplest, shortest way possible is the best way to appeal to business people who are suffering from information overload.

Important Words First

Because you don’t have a lot of space, and no control over how much of your subject line is visible in your recipient’s inbox – you want to put the important words first. Get straight to the point.

For example:

“Rate Reduction for New Subscribers”

Vs. “Info for New Subscribers: Rates Reduced”


“Deadline July 31st for Washington Residents”

Vs. “Residents of Washington Must Enter by July 31st”

Multiple Exclamation Points and Other Eye Candy Mistakes

The best way to avoid spam filters it to make your email not look like spam. Unfortunately, legitimate marketers have to pay attention to what spammers are doing these days so they don’t make the same mistakes and risk having their campaigns get caught in spam filters. Instead of immediately deleting everything, take a look at the email subject lines in your junk folder one day. It’s chock full of ideas for what not to do.

Things to Avoid in Your Email Subject Lines

  • All capital letters
  • Multiple exclamation points or other punctuation marks (Note: question marks are considered ok to use, but multiple questions marks will raise red flags with spam filters, not to mention your would be recipients.
  • The word “free” as the first word in the subject line. The word “free” is ok to use, but most email marketing platforms recommend not using it as the first word.
  • Overuse of other offer-type words, especially as the first word in the subject, such as: “complimentary,” “offer,” “entry,” “tempting,” “special,” “gift,” or “sale ends soon”

Things to Include in Your Email Subject Lines

There are a few different ways that you can structure your email subject line to get recipients to open them. What is important is that your subject line is relevant to what’s in the email itself and also relevant to your recipient. This is not the time to beat around the bush. This is the time to give – just the facts, Sir. Studies show that emails with a high degree of affinity to the recipient and which demonstrate benefits get the best open rates. Here are some examples.

Mention a Key Benefit to Your Recipient

  • Your May results are enclosed
  • Reduce your energy costs by $100 per month
  • How to Optimize Your Acme Product Tools

Target Your Recipient Through an Affinity

  • 10 Ways Acme Users Will Benefit
  • What Every VP of Sales Needs to Know
  • New Customers Only: Welcome Kit with Discount

Ask a Question or Make a Teaser Statement

  • Are you getting the most from your Acme System?
  • Are you familiar with all your profit centers?
  • What the Most Successful Acme Users Are Doing

Announce Something New or Yimely

  • New Product Update that Extends Life of Acme Tools
  • Early-bird registration ends Sept. 2nd
  • Just Released: Discounts for Acme Feature Set

Just as you might take a look at your junk folder to see what kind of subject lines to avoid, you can likewise pay attention to the news headlines and emails subject lines that catch your attention. Pay attention to the words and order of words and the message itself, and consider what got you to stop and click. Then think about how you can repurpose those ideas for your own use. Different subject lines will resonate with different audiences, so we be sure to test and measure the effectiveness of your email subject lines, and even ask recipients directly about what they like and don’t like about them.