Email Marketing consistently ranks as the highest return on investment digital marketing channel, providing higher returns than social media, display advertising, and many forms of content marketing. The major reason why some email programs deliver outstanding results and others do not is due to the team’s ability to interpret and act on their performance data or their not knowing what KPIs to track and how they should respond or take corrective action when they see the wrong trend. Email Marketing KPIs are critical indicators that indicate how well your overall email marketing program is functioning, whether it’s getting better or worse (declining). When tracking KPIs, it’s critical that you identify the correct ones and that when you see those indicators move in a negative direction, you take the appropriate action to correct it. This definitive guide to email marketing will provide you with every important email marketing KPI, what they measure, relevant benchmarks from previous years if available, and what you should do based upon your observations about these KPIs. If you are new to marketing by email or running a large email marketing program, knowing these numbers will help ensure your success.
Why Tracking Email KPIs Matters
Email marketing isn’t just about sending newsletters. It’s about data-driven decisions.
Tracking KPIs helps you:
- Understand what works (and what doesn’t)
- Improve engagement and conversions
- Reduce wasted effort and costs
- Personalize campaigns effectively
- Maximize ROI
Top Email Marketing KPIs You Must Track
Let’s dive into the key metrics that actually matter.
1. Open Rate: The First Impression Metric
The open rate is defined as a percentage of email opens. The open rate is calculated based on the number of unique opens divided by the number of emails delivered, multiplied by one hundred. Open rates are the most frequently reported metric used to evaluate email marketing success and provide insight into how effective a specific subject line has been, how recognizable your name is as the sender, and how appealing your preview text has been. Email open rates vary by sector, with not-for-profit organizations generally receiving email open rates over 25% and financial services typically receiving an open rate of between 20% and 25%, retail/e-commerce typically experiencing open rates of between 15% and 20%, and marketing/advertising companies usually receiving an open rate of between 15% and 18%. Please note that since Apple introduced Mail Privacy Protection (MPP) in 2021, email open rate measurement has become less reliable because MPP takes a preemptive approach to downloading email content (as a result of downloading prior to a person having opened their email), and as a result, MPP can artificially increase the number of emails that are opened by many users of iOS mail. Therefore, if your email list has a high representation of iOS users, open rates may be falsely inflated. Use the open rate as an indicator of direction, and use open rates to track trends over time; do not use open rates as an absolute measure of recipient engagement. If you see your open rate declining, investigate what has happened to improve your subject line performance, your sender reputation, or the hygiene of your email list before concluding.
2. Click-Through Rate (CTR): Measuring Content Engagement
The Click Through Rate (CTR), or click rate, is the percent of delivered emails that a recipient has clicked on at least once. You can find the CTR by dividing the total number of clicks (or unique clicks) by the number of delivered emails and then multiplying that result by 100. Therefore, the CTR acts as direct proof for how “compelling” your content or the call to action is in an e-mail, and when someone opens an e-mail and doesn’t click an action, it means they read your content but weren’t moved enough to take action. The lack of an action could mean the content isn’t relevant enough, the offer isn’t compelling enough, the CTA isn’t obvious enough, or they didn’t believe the links were sending them to the appropriate web page (less than trusted). The average CTR across all industries for email marketing emails is typically between 2% and 5%, whereas transactional emails (i.e., order confirmations/shipping notices) typically have a higher CTR, and newsletters would generally have a much lower CTR. To help isolate where your audience tends to click from/at, consider segmenting the CTR analysis from email type/audience segment/device type/send time. To improve the effectiveness of CTAs, you need to replace the less effective CTAs with stronger and more specific CTAs and systematically test link placement, button design, and copy variations.
3. Click-to-Open Rate (CTOR): Content Quality in Isolation
The Click-Through Rate (CTR) of an email indicates how many people clicked on a link in it compared to the total number of emails sent out. The Click-to-Open Rate (CTOR) measures how many people who opened the email went to the Link click through it to visit your website. CTOR gives you an idea of how well your email body content is performing separate from how well your subject line is or how good or bad your name is on the email.
For example, if you have a high number of opens and a low number of clicks, you will have a low CTOR. This tells you that your subject line worked well to get people to open your email, but the body content did not deliver the expectation set by the subject line. In addition, if you have a mid-range open rate with high click rates and CTORs, that indicates that your subject line is generally appealing to your audience; however, all of the people that opened the email were engaged with the body content.
As a general guideline, CTOR benchmarks typically range from ten to twenty percent across various industries; of course, your CTOR benchmarks may vary based on the type of email you are sending out and who your target audience is. When evaluating the effectiveness of your email body content, offering strength, layout, and the design of the call to action, use CTOR as your main measurement for determining the quality of your email body content.
4. Conversion Rate: The Business Outcome Metric
The most significant Key Performance Indicator (KPI) for determining the success of an Email Marketing Campaign is the conversion rate, as this measures how well email campaigns translate into measurable business results. The conversion rate is calculated by finding out what percentage of people who received an email actually performed the desired action (i.e., purchased, signed up for a webinar, downloaded information, booked a consultation, or some other defined action). To Calculate the Conversion Rate: Divide the number of conversions by the number of emails sent; then multiply the result by 100.
Tracking conversion rates accurately first requires tracking and measuring each conversion on your website following best practices. You must implement tracking on your website by either using Google Analytics Goals, eCommerce Tracking, or a Tracking Pixel via your Email Provider. Ensure that you use UTM Parameters on all links to your website in your emails to ensure clean attribution in your analytics program.
There are many conversion rate benchmarks, and they will differ drastically based on industry and type of email. For example, the average Promotional email converts at 1-3%; whereas, Abandoned Cart emails generally convert at a rate of 5-15%. Therefore, we recommend focusing on Improving Conversion Rate by Improving your offer, simplifying the Post-Click Experience, Relating your Landing Pages to the email containing clickable links to them and Reducing Friction in the conversion process.
5. Bounce Rate: Measuring List Health
The bounce rate of an email measures the percentage of the email messages that were sent that did not arrive successfully in the inbox of the intended recipient.
There are two different types of email bounces, and both represent very different situations under which you have a bounce.
1. A hard bounce occurs when the e-mail cannot be delivered (not successfully arriving in a recipient’s inbox) because of a permanent problem. The most common causes for a hard bounce are:
- A non-existent / invalid or incorrect e-mail address;
- A domain name that does not exist or has been disabled or deleted from the DNS; and
- A receiving mail server that has permanently blocked you from sending to them.
Once a hard bounce has been detected, you should remove that address from your e-mail list immediately because continuing to send e-mails to that address will harm your sender reputation and your overall deliverability.
2. A soft bounce (meaning no hard bounce) occurs when there is a temporary problem that prevents delivery (ex. Recipient’s mailbox is full; receiving mail server is temporarily unavailable, recipient’s inbox has too many messages in it; or the e-mail message is too large). Most of the time, e-mail soft bounces resolve by themselves; therefore, they usually require monitoring and often don’t need to be removed from your e-mail list until you have monitored them for a longer period of time than you did for the first soft bounce.
You should take any bounce that is a hard bounce, and if you have a hard bounce rate that is greater than 2%, it is a strong indication that you have serious e-mail list quality problems requiring immediate attention via e-mail list cleaning and/or improving your opt-in processes.
6. Unsubscribe Rate and Spam Complaint Rate
The unsubscribe rate is the percentage of recipients who unsubscribe from your email list after they have received a particular campaign. A normal unsubscribe rate is less than 0.5% per email sent. Unsubscribes are a part of life, as people’s interests change and so do their needs; however, high unsubscribe rates indicate that your content is not fulfilling the expectations of your subscribers. Reasons for high unsubscribe rates include too frequent communications, content that does not correspond with what subscribers initially subscribed to, generic, group-oriented, or non-personalized content, or potentially irrelevant subject matter given time changes. The spam complaint rate should be monitored as a high-priority metric. The spam complaint rate is the percentage of the total number of recipients who receive an email that subsequently mark the email they received as spam compared to the number of unsubscribes. An unsubscribe is an acceptable method of opting out. However, an email that is identified as spam is considered hostile and will negatively affect the reputation of the sender with the email service providers. If an ESP receives complaint rates of more than 0.08% to 0.1% for an email sender, they may block future emails from that sender. To have a spam complaint rate as close to zero as possible, you should keep a visible unsubscribe link in your emails, make sure that you are only communicating to people who opted-in, and send relevant and quality content to your subscribers.
7. List Growth Rate and Subscriber Lifetime Value
An Email List will always be in a constant state of growth and decline (natural increase/decrease). As a result, when measuring the email list growth, List Growth Rate is used, which accounts for both new subscribers as well as those who have unsubscribed or bounced off in order to come up with the “Net Growth” of your email list for a specific period. When you have a steady and positive List Growth Rate, this means that you are acquiring new subscribers and maintaining a healthy email list; when your List Growth Rate has either stagnated or declined, you are losing subscribers at a faster rate than you are gaining new subscribers, which limits the reach of your email list and potential revenue streams as time goes by. In addition, Subscriber Lifetime Value (SLV) represents the total amount of revenue generated from a subscriber while they were on your email list (by multiplying average revenue per email * average number of emails sent to the subscriber before they unsubscribed). By using SLV, you can make better informed decisions about how much you are willing to spend to acquire new subscribers, as if one subscriber generates $50 over their lifetime, the fact that it costs $5 to acquire that subscriber would be a very good investment.
8. Revenue Per Email and Return on Investment
Revenue per email (RPE) assesses how effective your email strategy is by providing a direct measurement of revenue generated from sending out individual emails: revenue generated from all emails delivered by the email marketing effort divided by the total number of emails sent out. RPE lets you determine how well different types of campaigns (promotional, newsletters, or automated) are working and monitor changes in the revenue generating performance of your email marketing strategy over time. Email marketing return on investment (ROI) compares total revenues generated by your email marketing strategy to the total expense incurred in operating the email marketing effort (this includes email marketing platform, design, copywriting, management time, etc.). Research indicates that among all forms of digital media/advertising, email consistently provides some of the highest levels of ROI, with some studies reporting an accomplishment for a typical retail email marketing plan of 30-40% ROI on emails sent out so long as each aspect of the email marketing effort is well-managed.
9. Deliverability Rate and Inbox Placement
The deliverability rate and inbox placement rate are both definitions that show how well emails are able to be sent and received by their designated addresses. The deliverability rate for emails calculates the total volume of emails that do not bounce when they reach an email service provider (e.g., someone’s email box). However, if the email has been “delivered,” then it may not have reached the inbox. The email may have gone into spam, into a promotions tab, or into other filtered locations after it has “been delivered.” The inbox placement rate calculates what percentage of delivered emails were located in the actual inbox instead of in an alternate location. The sender’s reputation (domain reputation and IP reputation), authentication of the email, the amount of email sent, the uniformity of emails sent over time, the quality of the email list, and the number of people who opened email in the past will all affect inbox placement. You can use automated delivery tracking systems (ex. Google Postmaster Tools) or the delivery tracking systems set forth by your Email Service Provider (ESP) in order to monitor your email deliverability.
10. Engagement Over Time and List Segmentation Metrics
A healthy email program not only captures individual campaign metrics but also tracks trends of engagement over time by looking across your entire subscriber base. For example, by looking at “Engagement Decay Analysis” to define subscribers by the decreasing level of engagement they’ve demonstrated over time (e.g., subscribers who have not opened or clicked through an email over the last 90 days or 180 days), brands can determine which Nvidia subscribers should be targeted with re-engagement campaigns prior to being suppressed or removed from their subscriber database.
Many brands measure engagement levels by segmenting their audience and comparing how different audience segments interact with their email (e.g., do the most recent customers appear to be more engaged than older customers? Do female subscribers click at a higher rate than male subscribers? Do subscribers acquired through your website demonstrate different behavior than those acquired through in-store sign-up? Overall, the above analyses can create increasingly refined segments and enable more effectively targeted and personalized emails, which optimally drive performance against all KPIs.
How to Choose the Right KPIs
Not every KPI matters equally. Focus based on your goal:
| Goal | Key KPIs |
| Brand Awareness | Open Rate, CTR |
| Engagement | CTR, Sharing Rate |
| Sales | Conversion Rate, RPE |
| List Growth | List Growth Rate |
| Deliverability | Bounce Rate, Spam Rate |
Conclusion
The measurement of success for email marketing is one of its greatest assets. Traditional types of marketing have many channels where it can be difficult to determine the effectiveness of the marketing effort. However, email marketing can provide measurable results by taking the recipient through the entire marketing process from the send to the open, to the click-through, to the conversion, and ultimately to the revenue generated. The Key Performance Indicators provided within this guide are representative of the overall health and performance of an email marketing program. These KPIs should be used for more than just reporting on outcomes; they can also assist in making informed business decisions. If a KPI is trending downwards, immediate investigation should take place to identify the underlying cause, implement a test to remedy the cause, and subsequently analyze the results of the test on that KPI. Results generated by email marketing programs that have a data-based strategy will consistently outperform their counterparts that rely upon their instincts.Fuerte Developers use email marketing to create highly targeted email campaigns for customers, which helps them connect with the right people and convert those connections into actual clients. Email marketing utilizes data analysis, effective content development, and automated marketing processes to help clients engage potential clients and increase conversion rates. In addition to email marketing, the use of Search Engine Optimization, advertising, and digital marketing all contribute to maximizing business growth and return on investment.
