11 Email Marketing KPIs and Metrics to Track Your Campaign's Performance

If you are an email marketer, you are probably familiar with the feeling of frisson. Do not let the word puzzle you. Frisson is the feeling of a thrilling shiver, the kind of fear-induced excitement when you are on a rollercoaster. Well... Email marketing is a kind of a rollercoaster, isn't it?

Email marketing is one of the biggest, if not the biggest, digital marketing channels. It is a very effective way to reach your target audience and supplement your company's growth. But how do you know you have reached the right person? Or met your goals?

In addition to email marketing tools, key email marketing metrics and KPIs (Key Performance Indicators) help you answer these questions.

In this article, we will take a look at 11 email marketing KPIs and metrics to track your campaign's performance or to plan your future emails:

1. Click-through Rate
2. Conversion Rate
3. Unsubscribe Rate
4. Bounce Rate
5. Open Rate
6. Click-to-open Rate
7. Overall ROI
8. List Growth Rate
9. Revenue Per Subscriber
10. Revenue Per Email
11. Email Forwarding / Social Share Rate

What is a KPI?

A key performance indicator (KPI) is a measurable indicator of performance and progress over a set period of time, evaluating whether a company is achieving its intended business objectives. KPIs provide insight into improvement and a strategic roadmap for decision-making while analyzing and providing goals for teams and individuals alike.

Without further ado, let's go over the eleven most important email marketing KPIs and metrics to track your campaign's performance:

11 Email Marketing KPIs and Metrics

1- Click-through Rate (CTR)

Click-through Rate, or CTR, is the percentage of email recipients who have clicked on the links in your email. It measures how well your campaign is performing. A recipient may open your email, which is great, but it is not great enough. When you send emails to your subscriber lists, you want them to complete a designated action.

To achieve that goal, your email content should integrate trackable links, make offers, and add call-to-actions (CTAs) so that these users can easily convert. 

The industry benchmark for CTR is around %4. You should maintain this percentage to have a successful email marketing campaign.

You can calculate your CTR rate by dividing the number of total or unique clicks by the number of delivered emails and then multiplying the result by 100.

For example, if you get 500 clicks and 10000 delivered emails, your CTR will be 5%.

The Click-through rate is also beneficial for analyzing the performance of your A/B tests. A/B tests usually experiment with new ways to get more clicks on your emails. Some A/B testing examples can help you get inspired! 

CTR also helps you understand whether your email subject is engaging enough to encourage people to learn more about your brand.

2- Conversion Rate

Conversion rate can be defined as the percentage of email recipients who not only clicked on the links in your email but also completed the desired action, such as a subscription for an event, booking a demo, purchasing a product, downloading a free e-book, etc. While your CTR can be helpful in measuring your content’s engagement level, conversion rate tracks if your offer and call-to-action are good enough to convert people.

Monitoring your conversion rate provides valuable insight into your email marketing strategy and achieving your business goals. To calculate your conversion rate, you can divide the number of people on your email list who completed the desired action by the number of total emails delivered and then multiply the result by 100.

In addition, conversion rate helps you determine whether you are seeing a return on your email marketing ROI. If people are clicking on your links but do not convert, you will be less likely to generate revenue in the long term. Therefore, adjusting your email marketing strategy is important to maintain profit.

3- Unsubscribe Rate

The unsubscribe rate measures the percentage of recipients who opted out from receiving your emails. It indicates that the people on your mailing list have received the given email in their inbox rather than the spam folder; however, they did not find your content valuable or engaging. Therefore, they stopped opening and reading your emails, so they eventually clicked the unsubscribe link.

Unsubscribe rate is one of the key metrics that calculate your email performance despite often being overlooked as a vanity metric.

Say, if you have recently started sending two emails a week instead of one and noticed a trend where people are rapidly unsubscribing from your email list, you may reconsider the changes you have made. 

However, it is also important to keep in mind that people who opt out of your emails leave voluntarily because they are not interested in your content anymore. That is why those who are still subscribed to your email list allow you to fine-tune your audience. 

4- Bounce Rate

Bounce rate, or email bounce rate, is the percentage of your total emails that could not be successfully delivered to your email subscribers. Email providers track bounce rates for every email you send to recipients and decide whether to accept your emails in their inboxes in the future or not.

There are two types of bounces you need to monitor: hard bounces and soft bounces.

Hard bounces usually result from invalid or non-existent email addresses, and these emails return to the sender because they cannot be successfully delivered. Once you notice hard bounces, you should delete the email addresses ASAP because they will never be delivered, and internet service providers measure hard bounces to determine your reputation.

Soft bounces, on the other hand, result from temporary issues or errors like a full inbox or server issue. The user receives your email, and their email address is correct, but because of the issues on the recipient's end, the mail bounces back. You can resend the mail once the issue clears up, or in some cases, the serves send it for you. 

To calculate the bounce rate, divide the total number of bounced emails by the total number of emails sent and multiply it by 100.

Tracking bounce rate is necessary for detecting deep-rooted issues with your email marketing campaign. The higher your bounce rate is, the more you are likely to be slammed by internet service providers as a spammer.

The industry benchmark is around 2%. To reduce your likelihood of being a notorious spammer, you need to move past the end boss... Spam filters. 

You can include spam complaints into this metric as it indirectly affects your bounce rate—poor deliverability, poor content, poor sender reputation, and so on. Once a user flags your emails as spam, you can be sure that they are somewhat annoyed. 

To reduce the spam complaints—and bounce rates— you can add a double opt-in form.

Usually, a person subscribes to your list, and that's it. However, making a subscription this easy may result in a flawed acquisition process. The double opt-in form sends another email link to the user in addition to the initial subscription mail to confirm their email addresses and have their consent to receive emails from your company.

5- Open Rate

Open rate is one of the most commonly used email marketing metrics. Tracking the percentage of recipients who opened a given email, open rate provides an insight into determining the value of your email content as well as assessing your subject line.

The downfall of the open rate as a key metric, on the other hand, proves it to be unreliable. It is because an open is registered only if the user also receives the embedded images in the same email. Therefore, if the user has their image-blocking enabled on their devices, they won't be counted towards your open rate.

Furthermore, when Apple introduced Mail Privacy Protection, the feature enabled Apple's customers to disable open-tracking, making the metric even more misleading for email marketers.

Considering that other providers will follow the lead of Apple's mail privacy protection, it is only necessary and cautious to consider other email marketing metrics.

6- Click-to-open Rate (CTOR)

It is probably better for your business to keep an eye on the click-to-open rate instead of the open rate.

Click-to-open rate (CTOR) is the combination of opens and clicks to give you a better understanding of your email campaigns' overall performance. In other words, CTOR measures how many people who opened your email actually clicked on the links. CTOR allows you to test the effectiveness of your subject line and email deliverability.

Did your subject line meet the expectations and deliver what it was offering? Or was it misleading your subscriber list?

To calculate CTOR, divide the number of emails clicked by the number of emails delivered and multiply the result by 100.

7- Overall ROI

Overall ROI (Return on Investment) is about how much money your email campaigns or email marketing efforts bring into your company minus the costs. It is a direct measurement of your total revenue divided by your total spend. Email marketing ROI works in a similar way because it can give you an idea about your overall ROI.

According to an eMarketer study, email ROI is around 122% which makes email marketing four times better than any other digital marketing channel. 

Also, for every $1 business spend expects a return of around $36, which directly proves why you should invest in improving your email ROI. In that way, you will see a higher percentage in email deliverability, conversions, traffic, revenue, and brand awareness.

To calculate your return on investment, subtract the email marketing cost from the revenue your email marketing campaign generated and divide that number by your campaign costs and multiply by 100.

8- List Growth Rate

The last metric on our list is list growth. List growth (or list growth rate) measures the rate at which your mailing list grows. It is one of the tricky email metrics because growth does not necessarily translate to high-quality email clients who will convert and improve your engagement rate. 

What you want is essentially engaged subscribers who click on the links, convert to buyers, read and potentially respond to your emails. Therefore, the list growth rate affects other email marketing KPIs when it comes to growing your business.

A positive list growth rate suggests that your subscriber list is growing on a regular basis because you deliver relevant content rather than losing subscribers at a greater rate.

To measure your list growth rate, after dividing the number of new subscribers by the number of unsubscribes, you need to divide the result by the total number of email addresses on your list. Then, you can multiply that number by 100 to get a percentage.

9- Revenue Per Subscriber (RPS)

Revenue per subscriber (RPS) represents the revenue you've generated from your every single subscriber. This metric informs you about the value of your customers and ROI. It allows you to identify which demographic group of your subscribers generate revenue and which don't.

Then, you can adjust your future campaigns to take actionable insights and focus your resources more on a specific percentage of subscribers and less on unengaged subscribers. 

10- Revenue Per Email (RPE)

We do admit that revenue per email and revenue per subscriber resemble each other quite a lot. So much so that it looks a little bit like this:

The difference between revenue per subscriber and revenue per email is that RPE bases its efforts on revenue that a single email generates, not the subscriber base. Revenue per email gives you the direct monetary gain (or email revenue) your emails produce so that you can try different trends and look at your email analytics to maximize your revenue.

If the email revenue is lower than you anticipated, on the other hand, you can revisit your activities on email marketing platforms and draw up a new plan.

To calculate revenue per email, divide your total email revenue by the total number of emails delivered.

11- Email Forwarding / Social Share Rate

Email forwarding or email sharing is one of the email engagement metrics you need to monitor. This metric tells you whether your emails are share-worthy. It indicates how many times a recipient shared your email through social media or simply forwarded to their friends, family, or colleagues. It is calculated by the "share this" button on your email.

You email design and email frequency affects the share rate. If you are not sending emails over a long time period, subscribers will forget who you are and what your business is doing. If your email design is too complex and hard to read, they will simply click away. Therefore, it is important to quality-check your email messages.

To find out the percentage of users who share your emails, divide the number of "share this" clicks by the number of total emails delivered and multiply that number by 100.

Final Words

Tracking the right email marketing metrics and KPIs matters for your business. There is no point in pursuing every metric available. You should be able to detect and sort the right metrics for your brand. It would help if you concentrated on the key email marketing metrics that will serve your goals.

With the right KPIs, you can easily measure and predict your success or shortcomings so that you always deliver what is the most suitable for your audience.