7 Key Metrics for Gauging Email Campaign Performance

Email marketing is all about building relationships, and so in many ways, it is a people business. At the same time, however, there are many aspects of email marketing that can and must be quantified if one is to achieve genuine success.

This can all sound a bit daunting at times, especially if you are just starting out and trying to grow a new business, but the tools provided through applications like Gmail postmaster can help you keep an eye on your most important metrics and solve potential issues.

So, what are the most important metrics in email marketing, and what insights can you gain from them?

Key metrics in email marketing

Performance metrics can be broken down into two basic categories: positive metrics which indicate success, and negative metrics which suggest areas of improvement. Let’s start by outlining the main positive metrics for campaigns:

Positive email metrics

  1. Your open: The open rate of an email is essentially what it sounds like – it indicates the number of recipients that open your mail after it arrives in their inbox. Though simple, it is a crucial metric, and you can think of it as the baseline of your campaign’s performance. If you have a healthy open rate, typically in the 20-25% region, then your campaign is off to a decent start. If not, your open rate can indicate issues with aspects of your email which give readers their first impressions, such as the header or subject line. 
  2. Your CTR: Your CTR, or click-through rate, is a broad indicator of success, similar to your open rate. It tells you how many of your emails have resulted in recipients clicking on one of your links. This can give you a general indication of user engagement, and whether or not your subscribers feel that you are offering something of value.
  3. Your CTOR: The click-to-open rate of an email is similar to its CTR, but more specific. Your CTOR expresses the number of unique clicks generated as a percentage of unique opens, and it can provide some actionable insights about your messages. For example, a message with a high open rate and a low CTOR means that your subscribers are opening your emails but choosing not to click on your CTAs (calls-to-action). This may suggest that your email’s main content is not fulfilling the promises put forward by your subject line, so you may need to align them more closely.
  4. Your conversion rate: Your conversion rate tells you how many of your subscribers have gone performed the desired action, upon reading your message. Conversions are highly important, and typically generate more purchases in email than other channels, so this metric gives you insights into the productivity of what should be one of your most productive channels. Moreover, helps you to know if you have marketed your product or service appropriately. If you are performing well in your other email metrics but not producing conversions, then the true value proposition of your product or service may not be as purported in your marketing copy.

Negative email metrics

  1. Your unsubscribe rate: It goes without saying why this one is a negative metric. After all, the last thing you want is to lose subscribers. However, understanding why people unsubscribe is the first step towards fixing the issue, so this information is crucial. Your unsubscribe rate will let you know if there are critical issues that could impact the overall success of your campaign.
  2. Your bounce rate: The bounce rate of your email expresses what percentage of your messages were unable to be delivered. Since bounces can have a serious impact on your reputation and deliverability, understanding your bounce rate is highly important. There are a  variety of reasons why your emails might bounce, and this metric helps you to get to the source of the issue.
  3. Your spam report rate: As you might expect, your spam report rate lets you know how many of the emails you sent out have received a spam report. As with your bounce rate, your spam report rate can critically impact your deliverability. This metric can give you insights into the issues with the design or frequency of your mail, for example, and indicates that emails need further testing or fine-tuning.


With email marketing platforms and tools like Gmail postmaster available to you, you have access to critical data such as the metrics listed above. These can help you to track your email campaigns and understand where you are achieving success. More importantly, they can show you where your campaigns have room for improvement, allowing you to take your email marketing game to the next level.

Literature Junkie, Marketing Specialist, and Content Producer. Writing quality content is my passion. Additionally, I love to listen to music every time no matter if I'm working or traveling.