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15 Email Marketing KPIs and Metrics You Must Be Tracking

Saffa Faisal

Remember baking your first cake? 

It wasn’t perfect - it needed more sweetness, 5 minutes less in the oven, and maybe some frosting on top. Eventually, after tweaking the recipe and tasting it multiple times, you got it right. Email marketing is no different. 

Just like the cake, email campaigns need to be tweaked to benefit from the complete potential of email marketing. By tracking email marketing KPIs, you can identify what needs to be fixed and what should be continued. 

This article explains 15 email marketing metrics you must be tracking and ways to achieve their desirable figures. Don’t forget to read how to use these metrics to achieve email marketing success at the end. 

What are Email Marketing KPIs? 

Email marketing KPIs (Key Performance Indicators) are benchmarks that monitor the performance of your email campaigns. No matter what your goals are - increasing revenue, nurturing relationships, or strengthening brand reputation, there is a KPI out there. 

You can monitor multiple metrics, but the below 15 are absolutely essential for campaigns that always perform well. 

15 Email Marketing KPIs and Metrics for Tracking Success

15 email marketing KPIs and metrics

To make things super easy for you, we have defined each of these powerful benchmarks along with how to calculate them, purposes for measuring them, and how their desirable figures can be obtained. Let’s begin;

1. Email deliverability rate 


This rate measures how successful email marketers are in getting their emails delivered to subscribers’ email addresses. 


Email deliverability rate = (number of emails delivered ÷ number of emails sent) ✕ 100%


You should be measuring the email deliverability rate primarily because of 2 reasons. A low deliverability rate is often a result of performing poorly in both these factors.

The first reason is to gauge the accuracy of your email lists. If the latter includes duplicate email addresses or ones with typos, you must reconsider your methods of getting subscribers. 

The second is your sender reputation. Oftentimes Internet Service Providers (ISPs) block emails because of poor IP/sender reputation. If that’s the case, you might witness a sharp decline in the number of delivered emails.


If we’re being honest, achieving a 100% deliverability rate is kinda impossible. With that being said, the higher the deliverability rate, the better. Anything above 90% deserves a pat on the back. 

A high email deliverability rate can be obtained through the following ways: 

  • Sending confirmation emails once someone willingly becomes a subscriber, aka double opt-in forms. 
  • Auditing your email list from time to time. 
  • Monitoring your sender reputation and choosing an Email Service Provider (ESP) with a high IP score. 

2. Inbox placement rate 


This rate measures how successfully an email has made its place in your subscriber’s inbox. This is not to be confused with email deliverability rate as the latter measures how many emails were delivered, not those received in inboxes. 


Inbox placement rate = (number of emails received in inbox  ÷ number of emails delivered) ✕ 100%


The main objective of measuring this metric is to identify how many emails are sent to your subscribers’ spam folder. There is nothing worse than emails getting flagged as spam since it affects the credibility of your brand and wastes the effort put in. 

Note - this email marketing KPI does not consider whether emails were sent to Gmail’s promotional or social tab. It treats all these tabs as one inbox. 


The higher the inbox placement rate, the better. 

Apart from maintaining a clean email list and maintaining a positive sender reputation, the spam folder should be avoided at all costs. 

Each email sent receives a spam score; if the latter is higher than an ISP’s predefined benchmark, the email is flagged as spam. 

To keep this score to the minimum, avoid using spammy words and ensure the emails are lightweight. Oftentimes, emails become heavier after embedding visuals. At Unlayer, all email graphics are stored on an external source, which ensures emails are light as a feather. 

To read more tips about avoiding the spam filter, read this article

3. Open rate 


The open rate measures how many emails were opened by your subscribers. 


Open rate = (number of emails opened ÷ number of emails delivered) ✕ 100%


The open rate determines the performance of your email’s subject lines. If the latter is interesting and catchy, you will be rewarded with maximum opens. If not, your open rate will be on the low. 

Open rate is also important when testing subject lines as you can track how changes made to them affect an email campaign’s overall performance. 


The desirable open rate is one that exceeds your industry’s average. The average across all industries is 25.85%, but you should be aiming to beat the average rate of your specific industry. 

You can achieve a higher open rate by ensuring subject lines are click-worthy. Create a curiosity trap by: 

  • Including numbers or emojis in subject lines. 
  • Asking a question or giving a strong statement. 
  • Adding humor or puns but carefully. 
  • Avoiding clickbaity subject lines that are not aligned with the email’s content. 

It’s also critical to mention here that you can’t measure the open rates of plain-text emails. So, if you want to monitor campaign performance, you must design and send HTML emails. Unlayer hosts more than 1,000 HTML email templates so you can track performance while easily designing attractive emails. 

Tracking open rates isn't as important as it used to be before. This is because of Apple's new privacy setting that preloads emails beforehand. This means that an email will appear opened even if your subscriber hasn't opened it. Thus, causing an inflated open rate.

However, this doesn't mean you entirely get rid of open rates; you must still optimize your subject lines for higher opens and use other metrics, discussed in this article, to measure performance.

4. Click-through rate 


This rate measures how many people clicked on one or more links within your emails. 


Click-through rate = (number of clicks ÷ number of emails delivered) ✕ 100%


There are multiple reasons why you must monitor click-through rates. For starters, it determines how engaging your emails are. The more clicks there are, the more your audience interacted with your emails. 

It can also signify your campaign’s performance. You would ideally want to redirect your subscribers towards a landing page, and clicks enable that. 

Click-through rates also gauge your audience’s interests. Let’s assume a makeup brand had 2 Call To Action (CTA) buttons in its emails, ‘Shop Lipsticks’ and ‘Shop Eye Palettes.’ If the lipstick CTA button got more clicks, it means that their subscribers would be more interested in seeing lip products. 


Like open rates, successful click-through rates are those that are above the industry average. However, a good CTR is between 2% to 5%

You can achieve maximum clicks through the following ways: 

  • Featuring CTA buttons instead of hyperlinked text. 
  • Ensuring well-designed CTA buttons that stand out in the email copy. 
  • Stacking up CTA buttons: one primary CTA along with multiple secondary ones. 
  • Writing CTA text in first-person viewpoint (I/me/my/we/our/us). 

Email Templates That Convert Crazy Good

Attractive Designs. Responsive Format. White-Labeled.
Email Templates

5. Click-to-open rate 


This rate tracks the number of clicks that came out of the people who opened the emails. The click-through rate considers the number of emails delivered, while the click-to-open rate considers the number of emails opened. 


Click-to-open rate = (number of clicks ÷ number of emails opened) ✕ 100%


This rate measures how your subject line and content perform together. If your email got many opens but not a lot of clicks, it means that while your subject line is attractive, the copy is lacking. 


You should be aiming to achieve a high click-to-open rate. For the latter to realize, subject lines and email copy must work as a team. 

Avoid clickbaity subject lines at all costs. They reduce click-to-open rates and increase unsubscribe rates and spam complaints. An email’s subject line must be aligned with the content. For example, if the subject line offers a 50% discount, the content should as well. 

The email copy must be of high quality and should maximize clarity and scannability. It should be written in a conversational style and focused on achieving only one goal. 

A low click-to-open rate might also be a result of poor email design. You might have been successful in capturing attention but failed at maintaining it. To design emails your subscribers can’t get enough of, follow these email design best practices

6. Conversion Rate


This rate measures how successful an email has been in achieving the goal defined. This doesn’t always mean how much revenue was generated, but it can be the number of event registrations, ebook downloads, or free trial sign-ups - you name it. 


Conversion rate = (number of actions completed ÷ number of emails delivered) ✕ 100%


The conversion rate is key for measuring the overall success of an email campaign. It also dictates how likely you are to achieve a high Return on Investment (ROI) on your email marketing efforts. 


A good conversion rate is one that exceeds the industry average, but the rule of thumb is that the higher the conversion rate, the better. 

This email marketing metric is directly related to how well your email’s CTA buttons are performing. Hence, ensure they stand out, include catchy content, and are positioned at a place where your subscribers are most likely to convert. 

3 tips for designing high-conversion CTA buttons

A low conversion rate may dictate a problem in your email customer journey. In such a case, you must examine the results of other email marketing KPIs to identify where the problem lies. 

7. Unsubscribe rate 


The unsubscribe rate shows how many people have willingly opted out from receiving emails from you in the future. They unsubscribe after opening an email that was sent. 


Unsubscribe rate = (number of unsubscribes ÷ number of emails delivered) ✕ 100%


The main objective behind measuring the unsubscribe rate is to see how relevant or interesting your emails are to your subscribers. Such emails are not necessarily spammy; if they were, recipients would have flagged them as spam instead of unsubscribing. 


A low unsubscribe rate should be your aim. The average unsubscribe rate is 0.1%. However, a relatively higher unsubscribe rate might be a blessing in disguise. 

With email marketing, your aim should be to reach a relevant audience instead of a large one. People who unsubscribe wouldn’t have converted in the first place, so not all is lost. With that being said, a high unsubscribe rate is still not favorable. 

Low unsubscribes can be achieved if your mailing list is accurate. Consistently auditing email lists and featuring double opt-ins ensure only the right people subscribe to your brand’s emails. 

If you witness a sudden surge in the unsubscribe rate, look out for something you’ve done differently. You might have started sending more emails or included way too many images. You can step it up a notch by asking people why they unsubscribed to get a better idea of what’s wrong. 

8. Bounce rate 


It measures how many emails were not delivered to your recipients’ email addresses.


Bounce rate = (number of emails bounced ÷ number of emails sent) ✕ 100%


To understand the purposes of bounce rate, it’s important to first know about its 2 types. A hard bounce is caused when an email is sent to an invalid email address; one that never existed or is now deleted. A soft bounce is caused when a recipient’s inbox is full or their server is down. 

Both hard and soft bounces are measured to ensure the legitimacy of email lists and the strength of the sender’s reputation. 


A low bounce rate is what you should be aiming for. 

One factor behind which ISP’s determine the sender’s reputation is bounce rate. So, if the bounce rate is high, the sender’s reputation will be poor, and so will be the email deliverability rate. 

Ensure a low bounce rate by verifying email addresses once subscribed and cleaning your email lists timely. 

9. Spam complaint rate


As the name implies, this email marketing metric tracks how many recipients flagged your email as spam. 


Spam complaint rate = (number of spam complaints ÷ number of emails delivered) ✕ 100%


This KPI measures how many people find your emails spammy. If the latter is more, there is a high possibility that your recipients’ ISPs will block you completely. Take it this way; when subscribers flag your emails are spam, they’re basically complaining to their ISP about your emails. 


You should be aiming for a low spam complaint rate. The acceptable rate is less than 0.1%, so ensure this figure is not crossed, or you’re at risk of damaging your reputation. 

5 ways to reduce email complaint rates

By following the below tips, you can ensure a low spam complaint rate: 

  • A familiar sender’s name, e.g., Sam from Unlayer, is used.  
  • Your email displays well and has a responsive design. 
  • Emails are lightweight. 
  • Subject lines and content are not spammy. 
  • The unsubscribe link is properly mentioned. 

10. Mobile open rate


This rate measures the number of emails that are opened on mobile devices. 


Mobile open rate = (emails opened on mobiles ÷ emails opened on all devices) ✕ 100%


More than 70% of people read emails on mobile apps. This statistic is enough to convince you on why you should be measuring mobile open rates. 


There is no right or wrong answer to this. If you find that your audience views your emails mostly on mobile screens, you must create responsive emails, i.e., emails display as intended on all screens. 

The easiest way to create responsive emails is to use responsive email templates. With Unlayer, you can be positive that emails load perfectly each time. The editor features a desktop and mobile preview option that lets you see how the email design displays on both screens. 

The ‘hide on mobile’ feature lets you hide certain elements on mobile screens while still showing on desktop ones. This ensures that emails viewed on mobiles are not unnecessarily long and provide a good overall user experience. 

11. Email sharing rate


This email marketing KPI measures how many people clicked on a ‘share this’ or ‘forward’ button on your emails. 


Email sharing rate = (number of emails shared/forwarded ÷ number of emails delivered) ✕ 100%


This metric aims to track how good and engaging your email content or offer is that it compels your readers to share on the message. Email sharing rate is critical for generating positive word-of-mouth and reaching out to a larger audience. 


You would want to maximize the email sharing rate. It can drastically improve your reputation and nurture relationships with your audience. 

Below are some tips on making shareable emails: 

  • Include social sharing buttons. 
  • Provide an incentive for sharing or forwarding emails. 
  • Feature an irresistible email design, including animations and interactive elements
  • Write engaging content. 

12. List growth rate


This benchmark measures the rate at which your email list is growing. 


List growth rate = [(number of new subscribers - number of unsubscribes) ÷ number of existing subscribers] ✕ 100%


The aim of measuring the list growth rate is to monitor how successful you have been in reaching out to new prospects. Email lists naturally decay by 22.5% each year, so it is critical to timely get relevant people on your list. 


The list growth rate is kinda tricky. While you should aim for a higher percentage, it should not come at the cost of including irrelevant people in your subscriber base. In other words, reach out to more people, but only if they are interested in hearing from you. 

You can achieve an impressive list growth rate through the following ways: 

  • Feature an irresistible lead magnet. 
  • Launch giveaways in exchange for emails addresses. 
  • Limit the number of unsubscribes. 
  • Place an opt-in form on your most visited web page. 
  • Participate in industry events and fairs. 
  • Leverage the skills of a lead generation company. 

13. Return on investment 


This email marketing metric measures the overall profitability of your email marketing efforts. 


Return on investment = [(campaign revenue - campaign cost) ÷ campaign investment] ✕ 100%


You must be tracking your email’s ROI to determine whether it’s a fruitful strategy for you or not. Email marketing has the highest ROI amongst all digital marketing channels. However, you should still determine if the return is high enough to make email marketing worth it. 


We kid you not; return on investment is everyone’s favorite email marketing KPI. Well, it makes total sense since you would want a high return against your investment. 

The average ROI for emails is 4,400%. In other words, $44 is earned at the expense of a dollar spent. However, this benchmark is more of an internal matter - it depends on the management on how profitable it considers an ROI to be. But, the higher ROI, the better. 

2 ways to improve email ROI

You can achieve a high ROI essentially through 2 ways; maximizing your revenue and minimizing your expenses. You can generate a higher email marketing revenue by offering limited-time discounts, benefitting from holiday email marketing, and sending targeted messages. You can reduce your expenses by using a free email design tool like Unlayer. 

14. Revenue per email 


This rate measures the revenue earned from sending a single email to subscribers. 


Revenue per email = (revenue from email ÷ number of emails delivered) ✕ 100%


The main objective of this email marketing KPI is to identify which email types are profitable and which ones are better left not sent. 


When analyzing the revenues earned against different email types, look out for common patterns. Does your audience prefer marketing emails over lead nurturing ones? Do they react favorably to persuasive or informative email copy? Do they like receiving emails on weekdays or weekends?

By playing around with these figures, you can conclude which kind of emails deserve to the sent frequently. 

15. Revenue per subscriber 


This rate calculates the revenue generated from each subscriber. 


Revenue per email = (revenue from email ÷ number of subscribers) ✕ 100%


The purpose of tracking revenue per subscriber is to determine the demographics, genders, and interests of subscribers who are the most profitable for you. You can then streamline your email marketing efforts towards the subscribers who bring you the most revenue. 


After calculating revenue per different subscribers, ask yourself; which subscriber brings me the most revenue? Identify common characteristics between them and write them down. For instance, your analysis shows that females are the most profitable out of all the genders. Hence, you should send them more targeted emails. 

You should also identify the subscribers who are on the opposite side of being profitable and then figure out ways to turn the tables around. 

How to Align Email Marketing KPIs With Campaign Goals?

Congratulations, you’re now aware of the most common and important email marketing KPIs. But should you be tracking all of them? Yes and no. 

While you should track all the above-discussed email marketing metrics, there should be a few important ones that you should heavily invest your time on. These benchmarks are the ones consistent with different email campaign goals. 

Below are some common email marketing goals along with the metrics that you should majorly focus on; 

  1. Increasing revenue > conversion rate, return on investment, revenue per subscriber, and revenue per email. 
  2. Improving engagement > click-through rate, click-to-open rate, email sharing rate, and conversion rate. 
  3. Growing subscriber base > list growth rate and unsubscribe rate. 
  4. Improving sender reputation > email deliverability rate, bounce rate, and spam complaint rate. 

How to Measure Performance With Email Marketing KPIs?

Using email marketing KPIs for improving performance

Okay, you’ve done the math, but how will you know if your emails are performing well or poor. Simple; just compare your figures with industry benchmarks, historical data, and predefined goals. 

Industry benchmarks 

Different industries have different averages for email marketing KPIs. For instance, the finance industry witnesses a higher open rate simply because no one would want to miss emails from banks or insurance companies. Contrastly, the open rate for the retail industry is on the lower end since most people don’t buy from each sale. 

Find the average email marketing metrics for your industry and then compare your figures with them. If you’re doing better than them, good job! If not, you need to spend more time on the strategy table. 

Historical data 

You can also compare your email marketing KPI results of a certain month/quarter/year with previous ones. This can identify whether you’re improving or not, as well as if certain changes made were profitable.  

It is relatively easier to compare the figures of different time frames since all of the information is available in-house. 

Predefined goals 

The first step of launching an email campaign is setting goals. At this stage, you can determine the desirable figures you want to achieve for different email marketing KPIs. Once the campaign concludes, you can then calculate the results and compare if you were successful in achieving them or not. 


We’re positive you’re now completely ready to track the success of your email campaigns. Just calculate the above-discussed 15 email marketing KPIs and compare them with the information available and you’re all set. 


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