Email Marketing

Power of Email Testing: Metrics Marketers Need to Know

Power of Email Testing: Metrics Marketers Need to Know
Bella Ward

If you're a marketer who's good with technology, it means you should know some basic marketing stuff, like how to track how well your marketing is doing overall.

Marketing metrics are numbers that marketers use to see how well their marketing is working. 

By keeping an eye on these numbers, companies can learn how effective their marketing plans are, find places where they can do better, and use data to make smart choices that help them grow and make more money in the end.

Importance of Email Testing in Marketing

Email testing is super important in marketing because it helps ensure that your emails are hitting the right notes with your target audience.

Consider sending out emails without knowing if they're reaching the people you want them to reach – it's the same as throwing darts blindfolded!

With email testing, you can make sure your emails are personalized and engaging, grabbing the attention of your audience right from the subject line. Whether you're using an email marketing tool or crafting emails on your own, testing lets you see what works best, whether it's the layout, the wording, or even the timing of your sends.

By testing different elements like email subject lines or the content layout, you can create emails that resonate with your audience and increase the chances that they'll open them up, read your blog posts, or take action.

In today's world where everyone's glued to their mobile devices, it's crucial to make sure your emails look great on screens of all sizes. Testing helps you ensure that your emails are mobile-friendly, making it easier for your audience to read them no matter where they are.

By testing different types of emails, like newsletters or promotional emails, you can figure out what your audience likes best and tailor your content accordingly. When you're growing your email list, testing can be a good idea to make sure new subscribers receive your emails and that they don't end up lost in spam folders.

Ultimately, email testing not only improves your email deliverability but also helps you create emails that drive traffic to your web page, keep your contact list engaged, and boost your overall marketing success.

Importance of Email Testing in Marketing

Important Metrics to Know

Marketing numbers include lots of important indicators that help check different parts of marketing work. 

There are more than a dozen email marketing numbers to keep an eye on, but we'll talk about 8 of the most basic ones here.

1. Open Rate

This metric indicates the percentage of recipients who opened an email out of the total number of recipients who received it. It's a fundamental measure of email engagement. 

A high open rate suggests that your subject line and sender name were compelling enough to prompt recipients to open the email and take a look at its contents. 

However, it's essential to note that open rates can be influenced by various factors such as the timing of the email, the relevance of the content to the audience, and even the sender's reputation.

Here’s the formula to calculate the open rate:

Open rate,

2. Click-Through Rate (CTR)

CTR measures the percentage of recipients who clicked on a link within an email or advertisement compared to the total number of recipients who viewed the email or ad. 

It provides insights into the effectiveness of your call-to-action (CTA) and the overall engagement level of your audience. 

A higher CTR typically indicates that your content resonates well with your audience, and your CTA is compelling enough to prompt action. Analyzing CTR can help you optimize your email content, design, and placement of links to drive more traffic to your website or landing page.

Here’s the formula to calculate the click-through rate:

Click through rate,

3. Unsubscribe Rate

The unsubscribe rate represents the percentage of recipients who opted out of receiving future emails from your mailing list after receiving a particular email campaign. 

While it's natural to see some unsubscribes over time, a high unsubscribe rate could indicate dissatisfaction with your content, frequency of emails, or targeting. 

Monitoring unsubscribe rates can help you identify potential issues with your email strategy and take corrective actions, such as refining your targeting criteria, improving email content, or adjusting the frequency of your campaigns to better align with subscriber preferences.

Here’s the formula to calculate the unsubscribe rate:

Unsubscribe rate,

4. Click-to-Open Rate (CTOR) 

CTOR measures the percentage of recipients who clicked on a link within an email relative to the total number of recipients who opened the email. 

Unlike CTR, which considers the entire recipient list, CTOR focuses specifically on the engagement of those who opened the email. 

A high CTOR indicates that your content is relevant and compelling to the audience who opened the email, leading to a higher likelihood of them taking action. 

By analyzing CTOR, you can gain insights into the effectiveness of your email content in driving engagement and conversions among your active audience.

Here’s the formula to calculate the click-to-open rate:

Click-to-open rate,

5. Bounce Rate

The bounce rate reflects the percentage of emails that were not successfully delivered to recipients' inboxes due to various reasons, such as invalid email addresses, server issues, or recipient email filters. 

Bounces are categorized into two types: hard bounces, which are permanent delivery failures typically caused by invalid or non-existent email addresses, and soft bounces, which are temporary delivery failures caused by issues like full mailboxes or server timeouts. 

Monitoring bounce rates helps maintain a clean and healthy email list, improve deliverability, and identify and resolve any underlying issues affecting email delivery.

Here’s the formula to calculate the bounce rate:

Bounce rate,

6. Spam Rate

The spam rate indicates the percentage of emails that were flagged as spam or junk by recipients' email providers and filtered into their spam folders instead of their primary inboxes. 

High spam rates can negatively impact your sender's reputation and deliverability, as email providers may perceive your emails as unwanted or unsolicited. Use our’s email warmup tool as it mitigates the risk of triggering spam filters, ensuring that emails land in the primary inbox. 

Factors that can contribute to high spam rates include sending emails to purchased or outdated lists, using misleading subject lines or content, or engaging in spam-like behavior. 

By monitoring spam rates and adhering to best practices for email marketing, you can maintain a positive sender reputation and ensure your emails reach the intended recipients' inboxes.

Here’s the formula to calculate the spam rate:

Spam rate,

7. Overall List Growth

This metric tracks the rate at which your email subscriber list is growing over a specific period. It's essential to monitor list growth to assess the effectiveness of your lead generation efforts and the health of your email marketing strategy. 

A steady increase in your subscriber base indicates that you're successfully attracting and retaining new subscribers, expanding your reach, and nurturing relationships with your audience. 

However, it's equally important to focus on the quality of your subscribers, ensuring that they are genuinely interested in your content and engaged with your brand, rather than merely chasing quantity.

Here’s the formula to calculate overall list growth:

Overall list growth,

8. Return on Investment (ROI)

ROI measures the profitability and effectiveness of your marketing campaigns by comparing the financial gains generated from your marketing efforts to the costs incurred. 

It's a comprehensive metric that takes into account various factors, including revenue generated from conversions, customer lifetime value, marketing expenses, and resources invested. 

Calculating return on investment allows you to evaluate the performance of your marketing initiatives accurately, identify high-performing channels or campaigns, and allocate resources effectively to maximize your return on investment. 

By analyzing ROI, you can make data-driven decisions, optimize your marketing budget allocation, and focus on strategies that deliver the highest returns for your business.

Here’s the formula to calculate the return on investment:

Return on investment,


The power of email testing cannot be overstated for marketers. Keeping an eye on your marketing numbers regularly helps you spot patterns, figure out what your customers like, and see which ways of reaching them work the best. 

When you know what's working well, you can make your marketing even better, spend your money wisely, and make sure your plans match up with what your brand wants to achieve. 

Use’s tools to figure out inbox placements, view spam results, and optimize your email send times.

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