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A/B Testing Emails: Best Practices to Follow

A/B testing emails give definitive insights into the target audience’s preferences. It presents better solutions to increase CTR and achieve a higher open rate.

In the marketing sphere, no strategy ever guarantees fully understanding consumers’ wants. Traditional methods like extensive research on buyers’ persona, changing content now and then, and relying on ‘gut feeling’ do not hold much significance in personalising email nurturing campaigns. It leads to a wastage of time and resources on content that the prospects might not even open.

Methods like lead segmentation and lead scoring make personalisation easier to some extent. But a void is still left in the marketing with the question of

“What will make the potential customers click?”

A/B testing of email campaigns solves this problem by directly asking the prospects what they want. So in this blog, I will explain the meaning of A/B testing emails and best practices that you can use to follow for optimising email nurturing sequences.

What is A/B Testing of Email Marketing Campaigns?

90% of content marketers say email engagement is the top metric they track to measure content performance. But what if the email engagement is not up to the mark? A/B testing is the answer.

A/B testing emails refer to sharing one variation of an email to a subset of prospects while sharing a different one with another subset of the target audience. At the end of the process, the variation with a higher open rate or CTR gets sent to all the other leads.

In email nurturing campaigns, various elements like subject line, visuals, content, etc., chalk up the conversion rate of an email.

By changing one email element at a time, companies can perform A/B testing for their email nurturing sequences and gain email copies that produce repeat business and new customers.

Some other prominent advantages of A/B testing emails include:

  • Helps in improving business performance
  • Saves time and cost-effective
  • Updates email designs according to consumer response

Things To Do Before A/B Testing Emails

Rushing into an A/B test might result in a failed experiment. Like all other marketing strategies, A/B testing also requires proper planning and initial preparation.

Here’s is what marketers need to do before implementing an A/B test:

a. Forming a Hypothesis

Changes done in an element of the email must have solid reasoning. Businesses need to form a hypothesis before implementing an A/B test. The hypothesis should precisely indicate the changes in the element, the problem it might solve, and what metrics it will improve.

For example, suppose a company plans to A/B test the subject line of an email; the hypothesis becomes: Change the subject line from “secure 50% off on the premium plan by March-end” to “Last chance to secure 50% off on premium plan” to create urgency and increase open rate.

b. Setting up Winning Criteria

Winning criteria refer to the factors through which the winning email variant will get selected. The winning criteria can be metrics like:

  • email click-through rate
  • spam complaint rate
  • unique and total open rate
  • unsubscribe and subscribe rate

A business can easily decide what winning criteria will be most suitable for A/B testing by formulating a hypothesis. For example, if the CTA button is under the A/B test, the winning criteria must be the click-through rate, as the changing of CTA will not affect the open rate or spam rate.

Email Elements You Should A/B Test

For A/B testing emails, marketers need to be aware of the elements and the best practices they must use to optimise emails. Below is a list highlighting all the prominent email elements companies can test for better marketing performance.

1. Subject Line

A subject line is the first thing a user notices about an email. Marketers personalise subject lines according to the content of the email and the receiving prospects. Catchy subject lines capture readers’ attention and encourage them to open the mail to explore the contents inside. It means that the subject line of an email is responsible for the open rate.

The subject line can be of many types, including:

  • Question
  • Offer
  • Teaser
  • Incentive
  • Urgency
Subject Line

No matter what type of subject line a company picks for their email, they must A/B test two things:

  • Word Length

The word limit of subject lines is still a topic of debate between marketers. A study done by Marketo tries to solve this question. They sent out 100,000 emails with different word counts in the subject line.

sent open rate

Marketo observed that four worded subject lines had the highest open rate while seven worded subject lines scored the highest overall.

For optimising the word length, companies need to keep in mind that users can access emails through smartphones. Businesses need to understand the most-used channel by their target audience and frame the subject line accordingly.

  • Word Placement

How you place your words in a subject line can make a huge difference. Sometimes companies might not know the prospect’s name, making it harder to personalise the emails. In such cases, marketers can use words that demand consumer attention and emojis that make the email look more friendly.

Word Placement

In the above image, we can see words like “Unlimited”, “special”, and “last chance” are placed at the starting of the email subject lines to intrigue the reader.

Emojis can also play a role in making subject lines look enticing. But remember not to overdo it. In the below example, the sending company has used emojis relevant to the subject line and found the perfect balance between creating striking short subject copies with fun-friendly emojis.

subject copies with fun-friendly emojis

Let’s understand how to test the subject line with an example:

how to test the subject line

In the above-marked email, the subject line is “How to use the content paraphraser tool to paraphrase with a 100% unique output? ”

The subject line is long and contains the catchphrase (100% unique content) at last.

Here, the subject line can be “Paraphrase with 100% Unique Content” to generate better open rates and be short, straight, and precise.

Here, variant A becomes the longer subject line, and variant B becomes the shorter one. Out of them, the variant which scores the highest open rate becomes the winner.

2. From:

Who has shared an email plays a vital role in marketing?

Companies that use the brand’s name in the FROM section of the emails ensure that prospects get reminded of the brand every time they open their mail. It helps gain more prospects’ mindshare and stay connected through brand name with potential customers.

But a recent study pointed out that using a personal name in the from section can increase the net open rate by 15-35%. All this makes writing the ‘from text’ complex for a business.

Marketers can consider three variations to A/B test their emails in the from section.

Company’s name

Company's name

A Personal Name

A Personal Name

A personal name followed by the company’s name

A personal name followed by the company's name

For example, I found Writesonic performing some similar tests.

Writesonic performing some similar tests

I assume ‘Team Writersonic’ had a higher open rate than ‘Aviva from Writesonic’, that’s why the company stuck to the former one.

3. Content

Content is responsible for the conversion rate of an email campaign. The tone of the copy, types of images, text size, relevancy of the content, etc., must resonate with the prospects. Due to the introduction of videos, gifs, emojis, and other forms of creativity in email marketing, it becomes difficult to pinpoint what to include and what not to include in the email copy, especially when you have to keep the content short.

A/B testing different email variations by tweaking creative elements in the email can help increase the click-through rate.

Let’s explore various examples from which businesses can take inspiration to understand what email changes they should test:

  • Simple text

These are traditional emails that have plain simple text followed by links.

semrush example for a/b testing emails
  • Utilising Images

Images help project the core message of the email more efficiently. In the example below, Zapier is a tool that allows businesses to integrate web applications. In this email, they teach readers how to design digital bullet journals and make their case effective by including an image of an already made journal. It familiarises the prospects with the possibilities in the Zapier tool and motivates them to learn more.

Zapier tool

Another example from Grammarly. They use eye-catching images and help keep the email length short while delivering the message precisely.

Grammarly example from a/b testing emails
  • Fun with Gifs

Gifs are a great way to interact with new clients and make them feel comfortable with your brand. These short clips add humour to the email copy and make prospective clients look forward to receiving more. Though, only through testing can marketers understand whether their leads like them.

Fun with Gifs in a/b testing emails

A/B testing simple text, images, and gifs in the email copy is an excellent way of understanding what the majority of the target audience prefers to receive in their emails. If the email campaign does not perform well even after changing these factors, then the company must consider a layout change.

4. CTA

Call-to-actions are the final step of conversion. Like landing page A/B testing, CTAs’ copy, colour, and placement must get tested for email nurturing campaigns.

a. Whether to use a button or text in the email campaign mostly depends on a brand’s aim behind it.

For example, if a prospect is at the top of the funnel, primarily educational content gets shared through email sequences. Instead of having buttons, the blogs should have links between the text that allows for maintaining the conversational tone of the email.

But if the business wants the prospect to perform an action after reading the email, then a CTA button might work better.

b. Placement and copy of the CTA are crucial. In the email copy, if the CTA gets hindered behind the image colours or at the bottom of the email, there are chances that it might go unnoticed. It becomes essential to run an A/B test to check the right placement and colour for the email’s CTA.

For example, in the email copies below, the left one contains CTA at the bottom while the email on the right contains CTA above the fold, middle, and bottom of the email.

A/B Testing Emails example

5. Sending Time

The timeframe when a prospect receives an email can affect the open rate and CTR. For example, emails delivered during holiday seasons will receive a lower open rate as most prospects will be busy with the celebration.

According to research, the best time to send emails is 6 a.m, 10 a.m, 2 p.m, and 8 p.m. Tuesday, Thursday, and Wednesday are the best when selecting days for sharing emails.

But general research can only help limit options for deciding the sending time of email sequences. Keeping these surveys in mind, companies must always do independent research through A/B testing emails and figure out the best time to send emails to the specific target audience.

Bonus Tips:

  • Check the preheader
    Preheaders are the text lines that follow the subject line in the preview. Marketers can test including the prospects’ names in the preheader along with emojis. It can affect the open rate of an email.
  • Try to involve more audience
    Always try to conduct A/B testing of email marketing workflows with a large audience base, unless the email sequence is a teaser for a new service or product, as it will produce more accurate results.
  • Calculate Statistical Significance
    To accurately check the results of an A/B test, businesses calculate its statistical significance. It is a method to ensure that the result produced by an A/B test is appropriately analysed, and then only changes get made to the original content. Companies interested in checking the results of their A/B testing emails can visit sites like VWO, Neil Patel, etc., to access a significance calculator.
  • Testing with patience
    Testing a single email element at a time helps understand the exact changes an email campaign needs to perform better. Be patient with the A/B testing process as it produces dependable results.


A/B testing emails should be the prime focus of every marketer that aims to increase open rate and CTR. By forming a hypothesis and creating winning strategies through market analysis, companies can test changes in their marketing campaigns. It becomes easier to develop conversion-focused email templates and helps build a better user experience for prospects.

Small or big emailing list, every business must perform A/B testing to optimise their email marketing channels for the best results.

If you want to know more about email nurturing workflows, then check out this blog:
A Simple Guide For Email Nurturing Campaigns With Examples

Also Check:

SaaS Website Best Practices to Optimize User Experience

Waseem Bashir
CEO of Apexure
Waseem Bashir
CEO of Apexure
Waseem Bashir
CEO of Apexure
Waseem Bashir
CEO of Apexure

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