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Best Email Subject Line To Get Marketing Emails Opened

Best Email Subject Line

Email marketing is one of the best ways to grow your business. It allows you to attract new customers and engage with them directly so you know who they are and how they are interacting with your brand. You can upsell and build stronger relationships with existing customers as well.

But first, you have to get them to open the email so they can get the message you are trying to communicate. This is why your email subject is so important and why you should educate yourself on the best way to create the best email subject line to get your marketing emails opened.

The best email subject line is the one that matches your content. This gives the receipt continuity, meaning that the email gives them what they expected when they open it. Don’t create clickbait or buzzword subject lines that don’t relate to the content of the email, this will pretty much guarantee they won’t open your emails any more, or worse they will unsubscribe from your list. There are some simple guidelines to follow for creating the best email subject line for your marketing emails that will improve your open rates.

  • Be direct and descriptive
  • Keep It Short 9 words or less
  • Use an email system that has a subject line helper tool
  • Only send emails to relevant segments of your audience
  • Review past subject lines with successful open rates

Good email subject lines not only get your current email opened but it increases the likelihood they will open emails from you in the future. Continuity between your subject line and your email message builds trust by providing them with what they were expecting to get.

Let’s go deeper into each of these to understand what they mean with examples and we will also share tools that will help make this process faster and easier.

Why Track Email Open Rates

In order to know if your subject lines are working, you have to track your email open rates. An email open rate is the percentage of the audience that you sent it to that opened the email. If you have 100 people in your audience and 30 open your email your open rate is 30%.

Tracking the percentage of the list opens is better than tracking the total number of opens when comparing open rates from split testing or against previous campaign open rates as the size of the audience will be different from email to email.

Open rates allow you to compare how well a subject line did regardless of the audience size. So for example, if the audience is 100 people with a 25% open rate for one email but 500 with an open rate of 10% for another we can determine that the subject line for the 100 people audience was better even though fewer people opened it.

Email Open Rates Benchmark

In order to know if your subject lines are effective, you have to determine if your email open rates are good. Good is a relative term, if they are consistent or increasing they are good. Ideally, you want a year or twos worth of open rates to look at from your email list, this is the best way to benchmark your emails. Not every company has years’ worth of data as many are start-ups or new to email marketing. For those that don’t have two years’ worth of data, there are alternative ways to determine the effectiveness of your subject lines. You can start with your industry average open rate benchmark.

In general, any open rate that is in the double digits, 10% or above is good. Then to get more clarity you can look at industry averages. While many marketing companies and smaller email marketing systems provide trends data we recommend using Mailchimps or Constant Contacts benchmark data. These are the two largest providers of email systems so their pool of data is bigger than smaller CRM systems.

Depending on your list size, and how warm the audience is your open rates can vary significantly from the benchmarks. Look at the benchmarks as a goal to reach by testing and improving your subject lines. Use your own account sending data to measure your short-term results from campaign to campaign. To really see the greatest improvement A/B test your subject lines on a small portion of your audience to see which performed better.

Another variable that impacts your open rates is how varied they are. If you have people on your list that have been on your list for a long time but never open any emails consider archiving them. They may no longer be in your target audience or the email goes to spam. Either way, if they are not engaged remove them. Many email systems charge by the number of email addresses you send to. Don’t waste your total number of emails in your plan on people who are not engaging with your content. A smaller more engaged list is worth more to you than a large list of people who are not interested in your content.

Best Email Subject Line Guidelines

There is no one subject line that will guarantee large open rates. The subject line’s ability to pique the interest of your community is based on how relevant it is to them with respect to your business. If you sell shoes and send a subject line about sharing a receipt for making cookies, you will probably get very low open rates because it’s not what your community expects to get from you. But if you send them an email with a subject line about the best shoes to wear while in the kitchen that will do much better.

Let’s walk through the top factors that influence subject lines’ open rates and some examples of how to implement them. This is based on what we see with our clients that whom we do email marketing.

Be Direct And Descriptive

The best email subject line is direct and descriptive. They tell the recipient what is in the email and if possible how it will benefit them or solve their problem. The next part of the article goes into detail about the length of the subject line, which is it has to be short. So short, sweet and to the point to get them to open the email.

Telling them what they are going to get in the email and be as descriptive as you can with as few words as possible is challenging. We recommend starting by writing out in as many words that you need what they are going to get and what you want them to do. Then from this statement pick the keywords and pull them together into a short phrase. It has to be just enough to get them to open the email, you can add the details in the email. So here is an example of how this works

Long paragraph for an email about the best shoes to wear while in the kitchen that are on sale for the month of July.

“Wearing the right shoes while cooking projects your feet, legs, and hip joints when you in the kitchen for a long time. Whether you are cooking for 3 days in a row for a special event or cooking is part of your job, you need the right shoes to help reduce fatigue. In the month of July, we are offering 25% off all of the fatigue-resistant culinary lines.”

Here is the subject line for the email

“Cook Much? 25% Off Fatigue-resistant Culinary Footwear

Preview Text: Your feet, legs and hips with thank you.”

The subject line conveys who you are talking to – cooks and what you are offering – a sale on footwear. Many email systems offer you the availability to create custom preview text which shows up directly below the subject line in most email system inboxes. You can use this space as a way to expand on your topic.

The Best Email Subject Lines are Short 9: Words Or Less

The reason the subject line is kept short is so that as much of the subject line is visible in the email preview as possible. Since everyone is different in how they set up their email inbox you have to assume that only 6 – 9 words are going to show. Here is an example of what the email preview looks like on my desktop setup.

When people use the preview panel on the left or right side to choose the email they are going to open the subject gets truncated. In this instance, you have got between 3 and 6 words before it gets cut off.

Many people read and review their emails on their phones now so the space is much smaller. Here is what the emails look like on my phone’s inbox.

My phone’s inbox provides a little more space for but the full subject line is still truncated.

In both examples, you will see the preview text under the subject line. This is where you get some extra space to convey your message. If it’s hard to keep your subject line short consider breaking it between two lines in order to convey your message. This should be tested as some people don’t have the preview turned on in their email system.

Use An Email System That Has A Subject Line Helper Tool

Trying to remember all the guidelines for subject lines can be a little time-consuming in the beginning. Its good to create a handy reference sheet or print and save this article. The other thing to do to help save time is to use an email system that prompts you on subject line best practices

The two email systems that we use and recommend are MailChimp and Constant Contact. Both have subject line helper tools that make it easy to remember the lengthen guidelines and then automatically let you know if you are within the range.

mailchimp subject line tool

Mailchimp shows you the prompts while you are writing your subject lines. As you are writing your subject line they let you know if you are meeting the best practice guidelines and where you need to make improvements. Here is a screenshot of what their tool looks like:

Constant Contact does it a little bit differently. They have an error checker that you can use to check the email and subject lines and if they see an issue they prompt you to edit the subject line then go back and recheck it. Here is a screenshot of what their tool looks like:

We prefer Mailchimps side-by-side tool while you are editing to get real-time feedback on how your subject line stacks up against the guidelines so you can get the best email subject line for your campaign.

Only Send An Email To Relevant Segments Of Your Audience

Many businesses provide more than one product or service for sale and have different target audiences for their different offerings. In this case, you don’t want to email your entire audience every campaign that you create, rather you want to be specific in your campaign and only send it to those who are interested in receiving it. It doesn’t matter how great your subject line is if you are sending the email to someone who isn’t in the market for what you are offering.

For Example, if you are a general contractor that does basement remodeling and also disaster restoration you have a couple of target audiences. One audience is homeowners that have basements and another is insurance agents that write homeowner policies. You would speak to these two audiences differently and the subject lines would be very different for a campaign you are sending about flood damage assessment after a recent storm.

The subject line for the insurance agents would be more about helping them help their policyholders in the event of a disaster. If you are creating a post-storm flooding email campaign the subject line could be “Schedule A Flood Assessment For Your Home Owners” The preview text could read “Friday’s storm caused record-breaking flooding in the city”

A separate email can go to homeowners where you have done basement redesigns with a different subject line. “Does Your basement Have Flood Damage?”. The preview text could read “Let us do a flood assessment to protect your basement remodel investment”

The best email subject line depends on who you are sending it to. In this case of an event-driven campaign, you will get better open rates if you customize your subject line and email for each audience.

Both MailChimp and Constant Contact allow you to group/tag audiences together to make it easy to send an email to specific audience segmentation.

Review Past Subject Lines With Successful Open Rates

The best way to get better at writing subject lines is to know what has worked and hasn’t worked in the past. You can determine if a subject line was successful by benchmarking it against your industry-standard as well as your past email subject lines.

To hone in on a great subject line for your email campaign A/B test different subject lines against a subset of your audience. Then once you get the winner of the A/B test check the winner and the loser against your previous subject lines to the same audience. Over time you will start to see what words and phrases get better open responses from your audience.

Constant Contact

Best Tools For Creating Email Subject Lines


The two email systems we recommend to create the best email subject line are Constant Contact and MailChimp. Both systems are great but they have different features so depending on the feature set you think is better for you will help you decide which to use.

Both have a tool that checks your subject line to see if it meets the guidelines for writing the best email subject line for your campaign. MailChimp has a quick link feature that allows you to look at your open rates of the last 5 emails you created and their subject line so you can decide what words you may want to reuse or get inspiration from. Constant Contact has quick links to suggested subject lines based on the content of your email. This feature is handy if you need a little inspiration on the initial creation of the subject line.

Both systems offer A/B testing so that you can allow your audience to give you feedback on which subject line is best for your campaign via the open rates.

I hope you found this article helpful in securing your business so you can stay focused on your growth goal which always includes marketing. Feel free to reach out via chat if you have any questions. We are always happy to answer questions. If you want our content delivered to your inbox Sign up for our newsletter. You get great content and exclusive offers by being a member.

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