Subject Line Secrets That Increase Open Rates

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Hannah Beadling
May 27, 2022
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min read

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If emails were a dish, subject lines would be the essential ingredient to the recipe. Yes, subject lines are actually more important than the content. 

Why? Because subject lines determine whether or not the recipient opens the email in the first place. Over half of email recipients decide to open an email based solely on the subject line. 

So if you want to increase the chances of getting those emails opened, it’s important to craft a unique and enticing subject line every time. 

They can also save your email reputation from SPAM reports on your domain. 

Approximately 7 out of 10 readers will report an email as SPAM after reading just the subject line.

Avoid SPAM trigger words like free, click, no cost, price, money, or give away because these might cause your email to get blocked by the recipient's filters. 

For a larger list of SPAM trigger words, check out these articles from HubSpot and  

There’s a number of pitfalls with email subject lines, but don’t worry! This week we will share three subject line secrets that will help you avoid the SPAM inbox, create intrigue, and get those prospects to click. 

Secret 1 - The Human Negativity Bias

People are naturally drawn to the drama of negativity. We’re hardwired to remember the negative responses more than positive responses. 

Use this fact to your benefit by appealing to human negativity bias in your subject lines. 

Phrases like “This is why 99% of people fail at___,” “The TRUTH they don’t want you to know,” “You’re doing ___ wrong,” “Worst ideas that cause people to___,” or “My awful experience with bad data” are all buzzy subject lines that catch your attention. 

These are great examples of how you can lean into that human negative bias and appeal to people’s desire to improve at the same time.  

Secret 2 - Don’t Be Passive, Give A Call To Action

Another way to increase open rates is by including a direct call to action in your subject lines.

Take a look at these two examples of subject lines: 

I thought you might want to take a look at this


Don’t miss these tips {Insert first name here}!! 

Of the two, the second subject line stands out more because it’s a direct call to action that generates curiosity. 

The first line is way too passive and has no urgency. Words like maybe, possibly, might, perhaps, suggest, and could are all examples of passive, vague language that you want to keep out of your subject lines. 

Make the reader feel like they have to open your email by being direct and straightforward with your subject line. 

Secret 3 - The Perfect Number Of Characters

What’s better, a short or a long subject line? This is an ongoing debate amongst email marketers. And it turns out there is an ideal amount of characters you want to leverage to increase your open rate. 

MailChimp claims that a subject line with less than 60 characters is ideal, with 9 being the least amount of characters they suggest using. Others say that less than 40 characters is best, and if it fits in the preview, even better. 

We’ve found that the perfect sweet spot is 6-10 characters. This range gets the highest open rates!   

Stick to that 6-10 character range and make sure your subject line is mobile-friendly by sending a draft to your phone. If the full subject line fits in the preview you’re golden. If the line gets cut off, shorten your subject line.  

Elevate your email game with these 3 subject line secrets to improve your open rates, test them out and see for yourself why subject lines are so important. 

After all, you can’t make more sales without more opens! 

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