16 Email Campaign Metrics and KPIs You Need to Track

Email marketing has a simple name, but a complex and diversified structure. It entails everything from mass emailing to branched strategies targeting different audiences, all of them designed according to the data. With data in focus, it’s crucial to monitor email campaign metrics, learn from them, and use them to define efficient workflows and customer journeys. And at all times, marketers should be aware of the constantly changing nature of email marketing and its metrics. 

For example, when Apple launched its Apple’s Mail Privacy Protection, things shifted, and measuring deliverability and success of email campaigns changed. Being on top of the latest email marketing news is important to understand which email campaign analytics to observe and how best to use them to the advantage of your overall strategy. 

Considering the differences between all types of email campaigns and their goals, the email campaign tracking process will differ as well. Still, there is a group of basic metrics you need to master and learn how to interpret and utilize their results.  

So, if you’re a business owner who wants to enhance your email marketing performance, maximize deliverability and increase revenue, this article is for you.

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What are email campaign metrics (KPIs)?

Email campaign metrics are KPIs or Key Performance Indicators of the success of email marketing strategies. They come in the form of data — numbers or percentages — showing how many people receive, open, or read campaign emails, how many of them click through links in the emails, and how many opt-out. Email marketing metrics enable businesses to learn if their campaigns are performing well, to understand their subscribers, and to improve their strategy.

Email campaign tracking is absolutely essential for building a smart, successful marketing plan and growing your business. 

Email marketing KPIs you need to use are deliverability rate, open rates, clickthrough rates, bounce rates, email list growth rates, unsubscribe rates, complaint rates, device statistics, and different business-relevant values.

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Why you should track email marketing metrics

In short – you need to track email marketing metrics to evaluate your campaign results. They will show if a campaign is successful, if the audience was properly targeted, and indicate room for improvement. Because they show data, the metrics will provide accurate insights into subscriber behavior and allow you to make informed decisions. 

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How to Decide Which Email Marketing Metrics to Track

Every email campaign is unique and should be treated as such, so deciding on the most useful metrics to track will depend on the campaign in question. 

To get a clear idea of what you will need, revisit your campaign goals — are you trying to generate leads, prompt a response, or get people to convert? Even if you have more than a single goal, you can determine priorities and narrow your choice of metrics. Make sure your goals are as precise as possible so you know what outcomes you need to measure. 

To give you an example: You may want to wake up your old subscribers, and you’ve set up an automated re-engagement campaign. What you want to know is how many of your emails got into the designated inboxes, how many people opened and clicked, and how many converted. Therefore, you will primarily observe deliverability, open and click rates, and conversion rates. Additionally, you may include more metrics pertinent to your business.

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How to Look at Email Marketing Metrics

Analyzing email campaign KPIs is of vital importance for your strategy – in fact, it’s, well — the KEY. The learnings you get from it will help you grasp the full extent of the value and progress in your email marketing program. Close monitoring your performance is, therefore, a must, and you need to apply the primary metrics right away, expanding the data you observe as you move forward. 

We at Campaign Refinery have studied email for years, and we find that it’s best to track all campaigns and their performance from a single interface. That is why our potent email service allows you to track all the relevant metrics easily and monitor your email marketing performance from all angles. Using our tools to craft and execute your campaigns will dramatically increase your deliverability, open rates, and engagement, and give you an unmatched email marketing experience. 

To assist businesses in setting up their email marketing operation, we’ve compiled a comprehensive list of metrics that will show exactly how to measure the success of an email marketing campaign.

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What Email Campaign Metrics Should I Track? 

There are primary email marketing campaign analytics you must track, but there are also those that relate directly to your business overall and not as much to the email campaign performance. Ideally, you should track all of them because each one will provide insight into a different aspect of your strategy and allow you to adjust and correct whatever faults may exist. 

Below, you will find a list of all the necessary metrics to track when measuring email campaign effectiveness. 

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1. Deliverability rate – Inbox Placement Rate 

• The gist: Deliverability rate shows the number of emails that make it to the inbox. 
• How to calculate it: By observing the open rates as a proxy.
• Be careful: Deliverability is NOT delivery! 

Delivery rate is the number of all emails delivered compared to all emails sent. It means the subscribers’ inbox providers received your emails, and they did not bounce. It’s the percentage of the total emails delivered over the total emails sent. 

Deliverability is a more elusive and much more useful metric. It shows the percentage of all emails sent and delivered to the recipient’s inbox. The difference is subtle, but if your subscriber’s provider has the email, it doesn’t mean it will end up in their inbox — and we mean in their primary inbox. Successful deliverability depends on your domain setup and authentication and your sender reputation. It’s something you can work on and improve. 

We at Campaign Refinery view the deliverability rate as the foundation of a healthy email marketing strategy. It’s a great indicator of a clean email list and a confirmation your emails are reaching their destination.

Measuring deliverability is tricky — we track it by observing the open rate. An email could reach the inbox and remain unopened, but still, an increasing open rate is an indication of improved deliverability. We’d say that if the open rate is between 30 and 50%, this indicates a healthy deliverability rate, while drops below 15% we would see as alarming.

Drops in deliverability rate — meaning drops in open rates — are symptoms of your email list’s declining health or of faults in your strategy. You could be sending to invalid addresses or spamming. Deliverability is the first step toward a successful email campaign.

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2. Open Rate

• The gist: Open rate shows the percentage of subscribers who opened your email. 
• How to calculate it: The number of emails opened over the number of recipients
• Example: 2000 opened emails / 10,000 recipients = 20% open rate

Why is measuring open rates useful? Knowing how many people open your emails can help you calculate the conversion rate and know how successful your email campaigns are. You should use it as a comparative metric to see if your open rates are improving or not, and use it as a variable for other calculations. 

Some platforms calculate open rates by using total opens instead of unique opens. This inflates the open rate number as some people open their emails multiple times. Campaign Refinery uses a unique open rate calculation as it is the most consistent for use in evaluating actual performance.

Having high open rates means you’re doing something right – your subject lines are enticing, or your subscribers are loyal and want your messages. Low or declining open rates show your approach or timing might be off, or your email list could use a clean-up. You should know that an email counts as “opened” only if the contact receives all the images within it. So, slow internet, heavy visuals, or complex content could also be the reason behind low open rates, even though those contacts might have read the text without the images loaded. Try to perfect those subject lines and stick to simple solutions in terms of content for more accurate open rates. 

It’s good to know that open rates depend on deliverability – nobody can open an email they don’t receive. 

What’s a good open rate? A healthy open rate goes above 20%.

There are several categories of open rates you should consider as well. 

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Mobile Open Rate

Mobile open rate shows the number of emails opened from mobile devices (phones and tablets). Since the majority of internet traffic is shifting to mobile, this is an increasingly important metric to observe. 

You may see an increase in mobile open rates during the weekend when people are less static in general. However, Apple’s Mail Privacy Protection (MPP) feature is likely to affect your measurements and stop you from tracking opens or seeing what operating system a subscriber is using. Therefore, you should know that the results — although relevant — may not be entirely accurate considering the inability to track mobile open rates for Apple Mail client users across all Apple platforms, including iOS, iPadOS, and macOS.

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Domain Open Rate

Domain open rates will show what number of people using a specific email provider open your emails. This can tell you if your emails are coming through a particular system or if they’re having problems with a particular domain’s spam filters. Knowing this, you can work to improve your sender reputation, which makes the domain open rate an exceptionally important metric. 

This rate will be affected by Apple’s MPP, but you will be able to track it for all other users. 

Campaign Refinery users love that we display a “Mailbox Performance Report” showing a breakdown per ISP and domain for the top 10 most common domains in the recipient list. This allows them to discover if they are having a problem with a specific domain/ISP they should address.

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Non-open rates

Non-open rates can be as important to monitor as any of the open rates. They will show you the number of campaigns your subscribers have not opened. 

Having high non-open rates for a particular campaign can show something is not working well, and you’ll need to perform A/B testing to see what it is. Figuring out the reason behind the non-open rates is a great learning curve and can significantly improve your campaign performance and the quality of your email strategy overall. 

Our experience tells us that the number 1 reason why open rates fall is that senders aren’t excluding subscribers who haven’t opened their messages in a long while. Reducing the email list to more recently engaged subscribers can often cure this. Campaign Refinery’s experts recommend senders to start working with their 30 Day-Openers and adjust up or down from there as they progress.

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3. Clickthrough rate — CTR 

• The gist: Clickthrough rate (CTR) refers to the content you send in your emails. 
• How to calculate it: Divide the number of unique clicks by the number of unique opens 
• Example: 3,000 unique clicks / 9,000 unique opens = 33% CTR

CTR can show you how your emails perform, how interesting or effective your content is, and if you need to improve your messaging, visuals, or call-to-actions. You should test your content prior to the campaign launch and find ways to create more engaging material. To get higher CTRs, you will need to place special focus on your CTAs and copy, leading your subscribers to more content they are most likely to want to discover. 

At Campaign Refinery, we measure unique clicks by unique opens as a more useful metric for performance analysis compared to measuring total number of clicks or opens. 

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4. Conversion Rate — CR 

• The gist: Conversion rate shows the number of subscribers who clicked on a link in your emails and completed an action towards your campaign goal. 
• How to calculate conversion rate: Total number of actions completed over the number of clicks
• Example: 300 purchases / 6,000 clicks = 5% CVR

The conversion rate (CR) is one of the primary metrics to observe. It will tell you the number of people who purchased your product or service or the number of ones who showed explicit interest in doing so, depending on your campaign goals. Meaning — you can track the number of paying customers and the number of new leads from different campaigns you launch. Ultimately, you need to know your CR to measure your return on investment and determine whether your business efforts are paying off. 

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5. Bounce Rate 

• The gist: Email bounce rate shows you how many addresses rejected — bounced — your emails. 
• How to calculate it: Total number of bounced emails over the number of emails sent
• Example: 363 bounced emails / 10,000 emails sent = 3.63% bounce rate 

It’s good to know that bounces can occur even when you do everything right. An email address given by the subscriber might be mistyped or fake, you could be facing spam complaints, or overall have bad email list hygiene that impacts your deliverability and sender reputation. Even though the best-maintained lists and senders can face some bounce rates, if yours exceeds 2% and continues to increase, you need to stop and reconsider your actions. 

First of all, you need to clean up your email list. This is a hefty task, which is why Campaign Refinery designed and integrated an automatic list cleaning tool that can help improve deliverability and open rates up to 6 times while ostensibly decreasing bounce rates. Our tools will take care of your soft bounces (temporary error emails, full inbox recipients, etc.) and get rid of your hard bounces (wrong addresses, role addresses, and other faulty destinations). 

To avoid high bounce rates from the start, you should use the double opt-in method and other validation tools to make sure your recipients want to get your emails and are sharing genuine addresses.

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6. Email List Growth Rate 

• The gist: This is the rate at which your email list is growing in size. 
• How to Calculate It: Take the number of new subscribers, deduct the number of unsubscribes and spam complaints, and divide over the total number of addresses 
• Example: (300 new subscribers – 80 unsubscribes and email/spam complaints) ÷ 9,000 email addresses on the list = 2.4% email list growth rate

The key to a successful email marketing operation is a healthy and long email list. Since there are bound to be some unsubscribers, you need to make sure to grow your list consistently by adding new, qualified subscribers to it. In fact, an expected email list decay is about 22.7% annually! The percentage at which your list grows is your email list growth rate, a metric telling you if your business is growing. 

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7. Unsubscribe Rate

• The gist: The unsubscribe rate shows the percentage of people who unsubscribe from your mailing list. 
• How to calculate it: Divide the number of unsubscribes by the total number of emails sent
• Example: 65 unsubscribes / 1,000 emails sent = 6.5% unsubscribe rate

Unsubscribe rate metrics are essential, and you will usually find them right on your main dashboard. Still, they don’t tell you the whole story because subscribers who may change their mind about your content might not bother and unsubscribe from your list. They may just stop opening your emails and engaging, becoming inactive subscribers. Therefore, the overall engagement is something you should view from all sides while you take care of your list. 

Remember to give your subscribers a super-easy option to unsubscribe, clearly visible at the beginning and end of your emails. It’s much better for you to have them unsubscribe than for your emails to be flagged as spam. This will help you build trust and long-lasting relationships with your interested subscribers as well. 

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8. Spam Complaint Rate 

• The gist: Spam complaint rate is the percentage of complaints your content receives per campaign. 
• How to calculate it: Total number of people marking emails as spam divided by the number of message recipients 
• Example: 15 spam flags / 1500 recipients = 1% spam complaint rate

Getting flagged as spam is a bad thing for an email marketer, and anything above 1% is a major red alert. It damages sender reputation as well as the results of future campaigns, but even the most attentive, high-quality, conscious senders can get a complaint once in a while. For example, Campaign Refinery’s clients are in obligation to keep their complaint rates below 0.1%, with the target being 0.05%. 

Spam complaint rates are an important metric because if they start to increase, you should most definitely react. Also, remember that you can only get complaint rates reports for non-Google addresses. To get your complaint rate from Google, you must use Google Postmaster Tools, and they calculate their rate differently. As a precautionary measure, you can make sure to follow the best practices of email marketing, avoid spam filters and create high-value content. And like we said – allow them to unsubscribe easily. 

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9. Engagement over time

• The gist: Engagement over time will show you if the number of people who engage with your emails is increasing or decreasing over a given period of time. 
• How to calculate it: Your email service provider should provide an insight into your open and click rates, as well as cumulative engagement rates.
• Why track it: Knowing how and when people engage with your email content will show you when are the best times to send which campaigns. 

We consider open rates a form of engagement, but engagement over time includes both opens and clicks. 

You can use email automation to change and adjust sending time to achieve better engagement in your email campaigns, but knowing the engagement over time for manual campaigns will provide insight into the content value and targeting. Most likely, the drops in engagement will show a change you made did not perform. 

For example, the Campaign Refinery analytics tool lets you view engagement over time in a graph, so you can get a visual idea of drops and surges while allowing you to go back to the specific emails and work out what it was that did or did not perform well.

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10. Device Statistics and Email Client Specs

• The gist: Device stats and email client (agent) information will show you which devices and email software your audience uses to read your messages. 

Learning about whether the device your contact uses is a mobile device or a desktop or whether it’s an Android or an iOS phone can help you plan your content better and know what metrics to consider. Screen size and other device specs affect display performance, which can be helpful when designing your messages, images, and CTA buttons. Also, tracking devices can help you segment your audience and send out specifically crafted content to particular groups of people. 

Similarly, knowing what email client your audience uses can help you know how to design your content, but also how to track your open and click rates. This has become especially important when Apple introduced Mail Privacy Protection, which disallows ESPs from obtaining users’ email activity data. 

We at Campaign Refinery believe that knowing about the device and email client specifics informs the campaigns and greatly contributes to better results, so we are soon adding a feature to track these metrics to our new, polished user interface.

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11. Email Production Time

• The gist: It’s the time that it takes to produce an email campaign. 

Email production time tells you how efficient your email marketing strategy is and allows you to identify improvement opportunities. Although this metric is not essential for email performance, it’s an important part of in-house budget planning. When tracking it, you should mind the time to actually write a single email, but more importantly — the time it takes to create a campaign from an idea to launch. 

When you know how much time and effort goes into a campaign, you will know what you invested, and you can better observe the overall performance. An efficient and lean email production process can help you achieve your goals faster.

Campaign Refinery, as an efficient email service provider that has all the necessary features, can help you streamline your email marketing processes. 

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12. Revenue per Subscriber — RPS 

• The gist: It’s the revenue a single subscriber brings to your business. 
• How to calculate it: Divide the revenue from your email list by the number of subscribers. 
• Example: $7500 revenue / 10,000 subscribers = $0.75 RPS

Revenue per subscriber can help you observe growth, segment audiences, and determine space for improvement or a different approach. If you incentivize your subscribers to purchase, lead them to click on CTAs, and inspire them to convert at every opportunity, you should see the RPS rates rise steadily. 

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13. Subscriber Lifetime Value — SLTV

• The gist: Subscriber (or customer) lifetime value — SLTV tells you how much money a contact is likely to spend while buying from you. It’s the value of a single customer relationship. 
• How to calculate it: First, you have to calculate your revenue per subscriber — RPS. Then, take the RPS number and multiply it by the number of months you’ve had this contact on your list.
• Example: RPS is $0.75 and you’ve had the subscriber for 10 months. $0.75 RPS x 10 months = $7.5 SLTV

SLTV serves to have insight into your strategy performance overall, because it takes the average purchase values in consideration over a longer period of time. It allows you to see which customers to nurture, which to engage, and which to let go when you look at different segments. Finally, the best way to gradually increase your SLTV is to engage with your subscribers regularly, incentivizing them often.

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14. Cost per Acquisition — CPA

• The gist: It’s the amount of money you spend to get a new customer. 
• How to calculate it: Total cost of a campaign divided by the number of conversions will give your CPA. 
• Example: $6000 campaign cost / 1,000 conversions = $6 CPA

Knowing what your cost per acquisition is can help you plan paid ads, giveaways, and co-marketing campaigns and even predict your revenue when combined with other metrics. It’s a useful business tool for tracking your investment requirements and your business growth. 

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15. Revenue per Email

• The gist: It’s the revenue of a single email campaign. 
• How to calculate it: It’s the total sales from your revenue.
• Example: You sold $1000 worth of products or services in one campaign. That is your revenue. 

Revenue per email is the key indicator of the campaign success if the campaign goal is conversions and sales. You cannot get it to drop too low or below zero. In fact, if your revenue is close to nothing, you have to change something in your approach because your business might not succeed without earnings. Also, shifts in email revenue can help you learn which campaigns are performing better and which ones to discontinue. 

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16. Overall ROI

• The gist: Overall ROI shows the percentage of return on your email marketing investment. 
• How to calculate it: Deduct campaign cost from campaign sales, and then divide by campaign cost. 
• Example: $10,000 campaign sales – $1,000 campaign cost = $9000 campaign revenue

$9,000 campaign revenue / $1,000 campaign cost = 9:1 return on investment — 900% ROI

We know email marketing is an investment with one of the highest ROI compared to any other digital marketing strategy — official statistics say it’s 36:1. Knowing this number for your business investment is crucial because it will show you if you’re running a profitable operation or just wasting money. 

To keep your ROI growing, you should run thoughtful campaigns, be considerate with your audience, have a clean list, and follow the best practices of email marketing. 

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17. Volatile Metrics (Bonus Wisdom): Forwarding and Email Read Rate 

If you made it this far, we figured you deserve a little bonus wisdom, so let us introduce you to the metrics that exist but have an exceptionally volatile nature.

Among all the metrics, there are ones that are almost impossible to track. However, it’s good for marketers to be aware of their existence to fully grasp all the facets of email marketing. 

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Forwarding and Social Media Sharing Rates

Email sharing rate shows the number of email recipients who clicked on a “share” or a “forward” button in your email, sharing your message on social media or forwarding it to a friend. 

Email forwarding or sharing is virtually impossible to accurately track. Even if you included share/forward links, most people will use the forward functions of their mail client. 

Still, enabling your users to forward or share your content is a good idea because it will allow you to generate new contacts and identify brand ambassadors. This is a great organic way to expand your audience and acquire new leads. 

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Email Read Rate — Reading Time

Email read rate shows how many of the opened emails were actually read. 

Although knowing whether your people actually read your emails, updates such as Mailbox Privacy Protection completely nuke this metric. Given the relatively low importance and an unproductive outcome, email read rate is something only a small minority of senders would track.

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Refine and Track Your Email Campaigns with Us

Having a clear goal, a smart strategy, and a high-performing email service provider can help your email marketing operations thrive. Knowing what metrics to track and how to use the data can make or break your efforts, and we are here to make your email analytics journey smoother. 

Our team at Campaign Refinery is dedicated to providing the best email service software to our customers, enabling them to craft all types of campaigns, send millions of emails each month, and track every aspect of their performance. Our UI tracks all opens, clicks, unsubscribes, complaints, and bounces, with a domain reputation feature coming soon. 

Our powerful set of email tools gives customers more options to stimulate engagement and therefore increase deliverability more than any other email platform on the market.

We hope you choose the right tool to send the best email campaigns for your business and measure performance. 

Until then, happy emailing!