How To A/B Test Your Email Subjects

A/B testing your email subject lines is one of the most impactful things you can do to increase your open rates and click-throughs.

In this article, we’ll show you how to A/B test your emails using Mailchimp’s split testing tool, which provides all the tools you need to make smart decisions about what email subjects are most likely to get noticed by readers.

We’ll also discuss some best practices for subject line creation before diving into a few tips and tricks for creating better-performing subjects in general.

Section 1: The Basics of Split Testing Your Email Subjects

Key Takeaways
– A/B testing email subjects is crucial for optimizing open rates and engagement.
– Create two versions of your email with different subject lines to compare their performance.
– Monitor metrics like open rates, click-through rates, and conversions to determine the winning subject line.
– Test only one variable at a time to accurately identify the impact of subject line changes.
– Use A/B test results to inform future email marketing strategies and refine your subject line approach.

Know Your Starting Point

Before you start testing, it’s important to know where your email list is currently at. This is called baseline data it means the current state of how your subscribers are engaging with their emails.

First, think about what your goal is for A/B testing. Is it clicks? More open rates? Higher conversions?

Next, take a look at your baseline data: How do subscribers respond to subject lines in general (and yours specifically)? What happens when they open an email and see the subject line that you’ve chosen? 

Do they click on anything else within that email? Do they unsubscribe after a certain number of unopened messages from you or other brands in their inboxes (known as “unsubscribes”)?

Last but not least, look at what your competitors are doing with their email marketing campaigns so far this will help give you ideas for what works best from an industry perspective.

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Form A Hypothesis

Before you begin testing, you should first have a hypothesis to test. The most common mistake made when conducting A/B tests is not having an educated guess about the results beforehand.

Your hypothesis must be testable and falsifiable: for example, if your email subject isn’t compelling enough to get readers to open it or click through, then it’s unlikely that any other part of the email will be compelling enough either (like a call-to-action). 

So your hypothesis would read something like: “When we change our subject line from ‘Hello World!’ to ‘Here are two things you need to know today…’, we will see an increase in open rates by at least 25%.

Test For Timing

When it comes to timing, there are a few things you can experiment with.

Test at different times of the day. You might find that your open rates differ widely depending on when you send your emails. 

For example, if you’re sending out a weekly newsletter on Sunday mornings and notice that the most popular time for people to read it is actually during their lunch breaks on Fridays.

Then you may want to shift your delivery schedule so that it arrives just before lunchtime instead of in the morning when people are still working or sleeping.

Try sending an email on different days of the week (and even months and seasons). 

Your open rate could be higher if you send an email later in the week or during a holiday weekend since fewer people will be checking their inboxes at those times (and maybe even more important because they won’t have as much anxiety about missing out on something fun!).

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Test For Subject Line Length

The length of your subject line is a huge factor in whether or not you get the open rates you want. But how do you know what’s best? 

The first thing to do is use a tool like MailChimp’s Subject Line Optimizer to test different subject line lengths. You can run up to 10 tests at once, so this should be fairly quick and easy for any company!

Next, take that test data and analyze it: Which subject lines performed best? And which performed worst? Take note of these statistics when creating new campaigns. 

If none of them performed well enough (meaning they didn’t meet or exceed your goals), then there’s still room for improvement but if some did perform well enough (which means they met or exceeded), that data can help guide future decisions as well!

Test with Numbers Or Lists

Use Numbers

A series of three numbers in your subject line might just be the trick, as it’s been shown to increase open rates by up to 20%. 

When writing email subject lines that use numbers, try to use a number-word combo like “7 Things”, “Top 5” or “12 Ways”. You can also insert any number between 10 and 999 in your subject line without losing its impact.

Use Lists

All about lists? Then you’ll want to test emails with lists in the subject line! Not only will using a list make it easier for your subscribers to skim through the content of your email and decide whether they’re interested enough to open it.

But some research suggests that including a list of benefits within an email subject line increases open rates by 56%. 

The best way for you to do this is by finding specific benefits related directly to what’s being advertised (e.g., “5 Reasons Why Your Brand Should Be Using Acme Software”).

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Use An Emotional Appeal

When you’re creating email subject lines, you should use words that appeal to your audience’s emotions. For example, if your product is something that would make someone happy or excited (like a vacation), you could use the word “happy.” 

On the other hand, if there’s some anxiety surrounding purchasing this product (like it might be too expensive), then “anxiety” could be a good word choice for your subject line.

Consider Your Audience’s Relationship With You

If you have a relationship with these users already (for instance, they’ve bought from you before), then consider using words like “love” or “hate” because these feelings are stronger than just liking something. 

On the other hand, if they’re strangers to each other but share a common interest (perhaps they both love Star Wars), consider using “joy” or “grief.”

Set The Right Tone Of Voice

The tone of voice you use in your subject line is the first thing that your audience will see, and it can make or break their engagement with your email. A/B testing subject lines is vital to understanding how your audience responds to different styles of writing.

You want to choose a tone that’s friendly, conversational, and matches the message you are trying to convey. Are you selling something? Then it should feel like a friend inviting another person over for dinner. 

Do you have tips on how someone can improve their life? Then perhaps humor (but not sarcasm) would work best here. Think about what kind of relationship you want with each reader as they open up their inboxes and then write accordingly!

Ask A Question In Your Subject Line

What?

Asking a question in the subject line is a great way to get your reader’s attention, but it can also be used as an incentive for them to open the email. 

For example, if you are writing an email about a new product launch or service offering and want to see if people will be interested in using it, you could use this type of question: “Do You Want To Save Money On Your Next Trip?”

Who?

This one is fairly straightforward it’s just asking who something is meant for. If you’re working on an email campaign geared toward teachers, you might ask “Who Needs A Break From Teaching?” 

This would be relevant since many teachers work long hours and weekends during their summer breaks and may need some time off during that period.

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Be Specific And Personalized

One way to create a more personalized email subject line is to use the recipient’s name. This makes the subject line more targeted and relevant to your subscriber, which increases their likelihood of opening and reading your emails.

You can also personalize the body of your email by using the recipient’s name in a sentence or two. Here are some examples:

• “I’m not sure if you’ve seen this yet, but there’s a great new dress at [store] that would look amazing on you!”
• “You’re going to love this new photo app that lets you add filters like those from [popular photo app]. It helps take pics from blah-y to fab!”

Another way to make sure an email feels personal is by including the recipient’s first name in a call-to-action button: “Click here now!” 

It may seem obvious, but think about how many times someone has sent something inappropriate through an automated system (like an order confirmation) with only their last name attached or worse yet, no identifier whatsoever.

Use The Recipient’s Name In The Subject Line

The first step is to use the recipient’s name in the subject line. This will help you create a more personal connection with them and make them more likely to open your email. However, you should use their name appropriately. 

If they are male and you are sending an email about skincare products, “Mark” might not be appropriate for the subject line because it is too casual for a man who may be older than 50 years old.

Instead of using his first name, you could use his last name or even something like “Mr./Mrs./Ms.,” depending on how formal your relationship with him is (if he is a client). 

On the other hand, if he works in marketing at your company as well as being an intern there then using “Mark” might make sense in this context.

Write To A Person, Not To All Recipients

You can’t write an effective email subject line without knowing who you’re writing it for. When writing your subject lines, don’t use “Dear Customer” or “Hello Friend.” 

Instead, use the recipient’s name in the subject line and try to address them directly as if they were an old friend or colleague. For example: “Hello John!”

Use A Friendly Tone

The tone of your subject line should be friendly and conversational just like any other email you send that isn’t promotional! 

If you’re unsure about how formal or informal the language in your message should be, ask yourself what would feel natural if this were a real conversation between two people? Does my tone sound sincere? Would I say these words out loud?

Offer Something Of Value In Your Subject Line

The next step is to offer something of value in your subject line. This can be an incentive, a contest, a survey, or anything else that’s relevant to the recipient. It could also be specific information about their account (like the number of days left on their subscription).

For example: “Learn how to add custom CSS styles with this free ebook”. If you’re sending an email newsletter, it could be something like this: “Would you like some tips on growing organic veggies? Click here!” 

Or if you’re running a B2B company then maybe it’s something like this: “Want to know our top 3 tips for increasing revenue by 15%?” You get the point!

Your objective here is simply to entice people enough so they’ll open your email and give what’s inside a chance.

Try Using Urgency Or Scarcity In Your Subject Line

Urgency and scarcity are two powerful psychological triggers that can be used to increase the open rates of your emails. In fact, according to a study from Salesforce, adding urgency or scarcity in subject lines can increase open rates by more than 200%.

That being said, how do you go about creating urgency or scarcity in your subject line?

You may think that it’s as simple as writing a subject like “LAST CHANCE!” or “HURRY!” But this isn’t always true. 

If you do it too often, people will start ignoring these types of emails because they know they aren’t really “last chances.” Instead, try using a little bit more subtlety with your messaging: 

“Only 3 Days Left!” or “Don’t Miss Out On Your Chance!” Both of these statements imply that time is running out on an offer or opportunity — even though neither one explicitly states exactly what it is.

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Be Clear And Concise With Your Message To Eliminate Confusion

Make sure your subject lines are clear and concise.

To keep your readers engaged, you need to make sure that the email subjects are clear and precise. 

If they don’t understand what you’re saying from just reading the subject, then there’s no point in sending them an email, right? You can avoid confusion by using words that are specific and relevant to your audience. For instance:

Don’t use jargon or industry-specific terms unless it’s appropriate for everyone in your audience (e.g., if most of your subscribers work in IT).

Avoid long sentences. It’s hard enough for people to read emails on mobile devices as it is! Keep each sentence short and sweet so that reading will be easier on them (and not cause them any frustration).

Don’t use complicated words when simpler ones would suffice unless you know that everyone who reads this information has studied a lot about this topic before (like how many doctors might study medical terms), stick with the basics instead of trying too hard to impress them with fancy words they don’t know yet!

Avoid Spam Trigger Words (At All Costs)

A/B testing your subject line is a great way to test the effectiveness of different subject lines and find the one that generates the highest open rate. However, there are some things you should avoid doing to make sure you don’t get flagged as spam by Gmail.

Do not use spam trigger words. This includes: “free”, “money”, “work from home” and “make money online”. The more obvious ones are easy to remember but other words can have negative connotations for Gmail’s algorithms, like “get rich” or “dieting”. 

It’s important to avoid them all so your email doesn’t get sent directly into someone’s spam folder before they even open it!

Use Suspense In Your Subject Lines Without Being Deceitful

When you want to add some intrigue to your subject lines, there are a variety of ways you can do so without being deceitful.

Here are 10 ideas:

Use a question. Whether you ask it in the headline or as part of the body content, asking questions is an easy way to get someone’s attention and make them want to open your email. 

This works best when you have something useful for your reader after they’ve responded, but even if all you have is another piece of information about the topic at hand, that’s still better than nothing!

Use a promise. Promises are another way to pique curiosity in your audience, they’re like little clues about what they could get out of opening up the email message itself and looking at what’s inside. 

The key here is making sure that whatever promise or guarantee gets made in the subject line holds once clicked on; otherwise people will feel misled and distrusting toward future correspondence from your brand (not good).

Conclusion

That’s pretty much it! Once you have your test ready to go, all you need to do is send it out into the world and wait for the results. The best part? You can start doing A/B testing on your email subjects now without any special software or training. 

Just create two different emails with different subject lines and send them out to a small segment of your subscribers (say 5% or 10%) using something like MailChimp or Campaign Monitor. 

From there, track which subject line gets more clicks (and opens) than the other before making a final decision about which one works better for you overall.

Further Reading

A/B Testing Email Subject Lines: Tips and Best Practices Short Description: Explore tips and best practices for effectively conducting A/B tests on email subject lines to boost engagement and open rates.

The Ultimate Guide to A/B Testing Email Marketing Campaigns Short Description: Dive into the comprehensive guide on A/B testing email marketing campaigns to enhance your strategies and drive better results.

Mastering Subject Line Split Testing for Email Campaigns Short Description: Learn how to master subject line split testing for your email campaigns, optimizing your content for higher click-through rates.

FAQs

How does A/B testing impact email marketing success?

A/B testing allows marketers to compare different variations of their email content, like subject lines, to identify which version performs better in terms of open rates, click-through rates, and engagement.

What are the key elements to A/B test in email campaigns?

Common elements to A/B test in email campaigns include subject lines, email copy, call-to-action buttons, images, and sender names. Testing these elements helps refine your approach for better results.

How do I set up an A/B test for email subject lines?

To set up an A/B test for email subject lines, you typically create two versions of your email with different subject lines, send them to a subset of your audience, and then analyze the performance metrics to determine the winning subject line.

What metrics should I analyze when evaluating A/B test results?

When evaluating A/B test results, pay attention to metrics like open rates, click-through rates, conversion rates, and overall engagement. These metrics help you gauge the effectiveness of the tested variations.

What are some best practices for successful A/B testing in email marketing?

Some best practices include testing only one variable at a time, using a large enough sample size, segmenting your audience for more accurate results, and implementing the findings from your tests into future campaigns for continuous improvement.