7 Formulas for Writing the Best Email Subject Lines

7 Formulas for Writing the Best Email Subject Lines


What’s the best way to increase your email open rates?

It’s by incorporating one of the best email subject lines we’re going to detail in this article below.

Did you know the average email open rate across all industries is 32%? Some industries see an open rate up into the 40th percentile, and some are lower in the 20th percentile.

If you’re currently seeing an open rate below average for your industry it’s time to make some improvements.

There are several reasons why your open rate could be low.

However, the most common reason that brands see low open rates is because of poorly written subject lines.

Today we’re going to deep dive into how to write the best email subject lines – you know, the kind that your recipients can’t wait to open!

To make things really easy, I’m going to share my favorite “subject line formulas” for achieving above-average open rates.

The Best Email Subject Lines You Can Use 

Every professional marketer I know uses email subject line formulas including myself. I’ve been sending highly successful email campaigns for over 10 years,  and I never spend more than 5 minutes thinking up a great subject line because I rely on these tried-and-true tricks.

1. The Lesson Formula

The Lesson Formula works extremely well for B2B companies and for some B2C emails as well. It’s written to inspire the recipient to open the email to learn something important.

How [blank] learned [blank] 

Examples of this subject line include:

  • How Fortune 500 Entrepreneurs Learned to Lead
  • How Busy Moms Learned to Juggle Responsibilities
  • How Overweight Men Learned to Get Fit in 90 Days
  • How Jake Gyllenhaal Learned to Act
  • How Beginner Marketers Learned to Write Great Subject Lines

The reason this subject line formula performs well is that it promises to teach the recipient something that other people have been successful at. This means “it works” and can be done, which is promising!

2. The Results Formula

The Results Formula is very similar to the Lesson Formula in that it’s all about sharing an important tip or life hack with the recipient.

How [Blank] Achieved/Did [Blank] 

Examples of this subject line include:

  • How Facebook Convinced Peter Thiel to Invest Millions
  • How Snapchat Grew to 1 Million Active Users Fast
  • How This Couple Saved 3 Million and Retired in Their 30s
  • How This Couch Potato Trained to Run a 5K in Just 3 Months
  • How This Women Trained Her Dog to Say I Love You

The Lesson and Results Formula only work well if the lesson you’re teaching is interesting to the recipients. For example, don’t send an email on dog training lessons to someone who might not have a dog. Make sure your email and subject line are relevant to the recipient and that’s half your battle.

3. The Urgency Formula 

Creating a sense of urgency is one of the best ways to get an email recipient to open your email because if they don’t they’re going to miss out!

Only [Blank] Hours Left to [Blank] 

Examples of this email subject line include:

  • Only 5 Hours Left to Register for Conference
  • Only 24 Hours Left to Sign Up for Webinar
  • Only 12 Hours Left to Save 25% on Everything in the Shop
  • Only 1 Hour Left to Save 15%
  • Only 48 Hours Left to Sign Up for the Marathon

This formula works great if the amount of time left is scarce.

I would suggest that 48 to 72 hours is about the farthest out you can use this.

First, because you are trying to create a sense of urgency and anything more than 3 days doesn’t feel like I need to rush. Second, because most people know that 24 hours = 1 day, 48 hours = 2 days, 72 hours = 3 days. However, off the top of our heads, we may not know that 96 hours = 4 days.

Anything further than that gets confusing for non-mathematicians!

4. The Scarcity Formula 

This formula is a great compliment to the Urgency Formula, and can often be used together to create great email subject lines!

Only [Blank] Left

Examples of this subject line include:

  • Only 15 Taylor Swift Backstage Passes Left!
  • Only 50 Eyeshadow Pallets Left in Stock!
  • Only 10 Spots Left in Saturday’s Spin Class!
  • Only 20 Reservations Left for Valentine’s Day Dinner!
  • Only 5 Spots Left in My Online Consulting Course!

With the right planning, you can use this subject line together with the Urgency formula to increase your results. For example, if you are a race organization you might do the following:

Send email one, two days before race registration closes:

Only 48 Hours Left to Sign Up for the Marathon! 

Send email two 1 day before race registration closes:

Only 5 Spots Left in the Marathon! 

This is a great two-pronged email strategy for getting people to take advantage of what you have to offer at the last minute.

5. The Don’t Buy Until Formula

If you’re selling a product or service that people may be skeptical about, the Don’t Buy Until formula is great for installing confidence in the purchase.

Don’t Buy [Blank] Until [Blank]

Examples of this subject line include:

  • Don’t Buy Photoshop Until You Read This Review
  • Don’t Buy a Gym Membership Until You Watch This Video
  • Don’t Buy a Waist Trainer Until You See These Before & After Pictures
  • Don’t Sign Up for Conference Until You Review This Event Schedule
  • Don’t Buy Tickets to Disney Until You Read These Tips for Saving Money

This email subject formula works really well if you captured someone’s email address because they indicated they wanted more information about your product or service. It’s informative and non-threatening but still allows you to make a direct call-to-action at the end.

6. The Desired Result Formula 

This subject line formula is great for convincing someone that they really need your product or service to achieve some result they’re after. There are multiple ways you can write this subject line, the key takeaway is that you must always include the desired result.

[Blank] [Desired Result] [Blank] 

Examples of this subject line include:

  • Lose 5lbs This Week Drinking This Smoothie
  • Increase Your Revenue by 5% With This Tip
  • Find an Investor for Your Startup With This Strategy
  • Make $1,000 Extra Per Week With This Side Hustle
  • Buy Your Dream Car With This Insanely Good Loan Offer

Of course, you need to truly include some great actionable tips or offers in your email so that there is a good payoff based on the subject line. However, if you can offer good information you’ll earn the trust of the recipient. Then they will open all of your future emails to get other great information and offers!

7. The Personalization Formula 

On average personalized email subject lines are 22% more likely to be opened than non-personalized subject lines. Some audiences won’t like personalized email subject lines because they’ll consider it creepy, not understanding how the technology works – but this is definitely something worth trying!

A [Blank] for [name] or [Name] Take Advantage of [Blank] 

Examples of this subject line include:

  • A Special Introductory Rate for Karen
  • Karen, Take 15% Off Today Only!
  • Karen, Take Advantage of This 25% Off Discount Code
  • Free Gift with Purchase for Karen
  • A Special VIP Upgrade for Karen

There are many ways to use personalization in subject lines, have fun with it!

A/B Test Your Email Subject Lines

Using proven email subject line formulas is one great way to increase your open rates. You can take the formulas one step further by A/B testing two subject lines against each other.

The best email subject line will reveal itself to you after the test!

For example, let’s say you own a gym and want to increase signups for your Monday night spin class. You could use the Results Formula and send an email with the subject line: How Jenny Lost 10lbs Taking Spin Class Last Month. Alternatively, you could use the Personalization formula and send an email with the subject line: A Special $5 Spin Class Discount Just for Karen.

How do you choose between the two? You could go with your gut and make the call on your own, but there’s a better way. You can let your audience tell you which one resonates with them better by running an a/b test on your subject lines.

Split Testing to find the Best Email Subject Lines

You would do this by randomly sending an A/B test of your subject lines to 25% of your email list and seeing which one generates the highest open rate. You would then use the winning subject line to send the email to the remaining 75% of your list!

Every email marketing platform requires setting up an A/B test slightly differently, but almost all of them offer it.

Here’s a helpful guide for the most popular platforms:

As you get started, keep in mind that there are many factors that go into achieving an above-average open rate on emails. If you have a bad email list, where the users didn’t clearly opt-in for information from you, the open rate from that list may always be poor.

If you have a healthy opt-in list of consumers interested in what you have to offer, use these great email subject formulas to help you increase your open rate and generate better email marketing results!


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