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11 Valuable Email Marketing KPIs You Must Track

by Nedim Talovic · Updated 25 Feb 2022}}

You probably know that email marketing is the best marketing channel. The big reasoon for that is its ROI. 

The fact is that email marketing has 2.47 times better ROI than SEO, and even 2.35 times better than keyword ads.  

Email Marketing ROI

To make the most out of it you need a good email marketing software. It will take your email marketing to the next level, improve customer engagement, and improve your business in genaral.

KPI stands for Key Performance Indicator, and basically, KPI’s are the most important metrics in the particular field. In our case, it’s email marketing. 

In this blog post, I’ll explain 11 email marketing KPIs that you really should track today. Here are they:

  1. Number of Subscribers
  2. Growth Rate
  3. Open Rate
  4. Click Rate
  5. Unsubscribe Rate
  6. Bounce Rate
  7. Lead-To-Conversion Rate
  8. Delivery Rate
  9. Cost per Lead
  10. Email Sharing Rate
  11. ROI

Let’s explore them!

#1 Number of Subscribers

I know lots of people will say quality over quantity, and I couldn’t agree more. But, when I talk about quantity I mean the quality included.

Although all the rest metrics below have their formulas, for a number of subscribers there’s none. You only have to count all emails you get.

Here, I’ll mention TWO methods of increasing the number of subscribers.

Method #1: Content Upgrades

Obviously, the most efficient method is a content upgrade. The concept is ultra simple:

  • Create amazing piece of content (blog post)
  • Offer more

Here’s my example. I created Content Marketing Quotes article where I questioned top content marketers for a few sentences (general thoughts, predictions..). I’ve created a one PDF document where you can download and print the most important sentences.

Content upgrade example

But, whenever someone clicks on DOWNLOAD, this is what appears.

Content Upgrade Dialog

The visitor must write his name and email if he or she wants to download the file.

Method #2: eBook

The method that requires some time because writing a book and a blog post isn’t the same. Your book will have a lot more words than blog posts.

The simplest way to find a topic is using Quora. As an example, I’ll open Marketing topic and see what people are interested in.

Marketing feed on Quora

The photo shows that writing about building a perfect marketing SaaS team might be great since every student is trying to build is SaaS company. 

Finally, once I create a book, I’ll have to promote it. I can advertise on Facebook or put it on the right side, for example. Here’s how Jeff Bullas promote his eBook.

Jeff Bullas' Sidebar

Furthermore, inserting the link in blog posts where I mention the book about marketing SaaS will increase the number of visits to the landing page.

#2 Growth Rate

Just like the number of website visitors, your email marketing list has to grow. Here’s the formula.

List Growth Rate

For example, if this month you acquire 1,000 subscribers, lose 15 subscribers, and you have one email/spam complaint while you in total have 10,000 subscribers, it means that your list growth rate will be 9.86%.

You should always check which pages and posts give you the biggest number of subscribers. According to Pareto Principle, the top 20% of pages will bring 80% results.

Pareto principle

So, open the first 20% pages and check if there’s something to optimize. I’m pretty sure that you’ll find something - A/B tests are waiting for you.

Now, I mentioned some of the ways of increasing the number of subscribers, but I’d like to add some more:

  • Content upgrades
  • eBooks
  • Facebook lead generation ads
  • Modal dialogs
  • Quizzes
  • Webinars
  • Testimonials
  • LinkedIn Ads
  • Live chat
  • Sidebar slides

The two methods that usually have high rates are content upgrades and eBooks. Of course, Facebook lead generation ads also bring lots of new subscribers, but here I’m talking about freeways that are the most useful.

#3 Open Rate

Everything begins with the open rate. Sending 10,000 emails that result in 2,000 opens means that your campaign had an open rate of 20%. The formula is here.

Open rate formula

If you think that 20% isn’t The two methods that usually have high rates, I completely agree with you. But, the benchmarks don’t show anything better, either.

Opens and clicks

For example, the fashion industry average open rate is 19,61%. Different factors influence the open rate, including:

  • List size
  • Industry
  • Time of day
  • Subject line length
  • Number of emails you send a month

Take a look in numbers what impact the subject line has on open rate

Subject line length and average read rate

Having a subject line from 61 to 70 characters had a 17% average read rate - the highest of any length, according to this study.

Keep in mind that displays of mobile devices are limited. Look how iPhone 6S displays subject lines.

Emails on iPhone 6S

Next, a number of monthly email campaigns will definitely impact email open rates both for B2B and B2C.

B2B vs B2C Email Open Rate

For B2C companies, sending 6 - 15 emails should have the highest open rate, while for B2B companies that number should be 16-30 newsletters per month.

I don’t know for you, but I’m not interested in sending 30 emails a month to one subscriber. That’s simply too much.

#4 Click Rate

Once someone opens your newsletter, the work has just started. The marketer must create the most attractive emails to lure the subscribers to click on them. The best measure is click rate.

Email CTR Formula

As you can see, sending 10,000 newsletters with 2,000 opens and 315 clicks means that your can click rate is exactly 3.15%.

Some email marketing specialists track the number of unique clicks which is also very good. Now, here are some of the mistakes that lead to the lower click rate:

  • Responsivity Issues
  • Lack of Photos
  • Not optimizing CTA
  • Not sending personalized emails
  • Avoiding Segmentation

The industry data says that the Advertising/Marketing industry has the best click rate.

Email benchmarks by industry

On the other side, the Education industry has the lowest click rate.

#5 Unsubscribe Rate

It will happen often that someone subscribes and unsubscribes after a while. You shouldn’t have a problem with that. There are various reasons why would someone unsubscribe:

  • Boring newsletters
  • The content isn’t relevant
  • You send too many emails
  • Unprofessional emails
  • Too promotional

The unsubscribe rate formula looks like this.

Unsubscribe rate formula

Even if you have amazing content, sending lots of newsletters a month will lead to a higher rate. Too many emails will make subscriber's inbox hard to check.

Impact of monthly email campaigns on email click rate

Your job is to find a sweet spot. The photo above shows us that if you send more than 30 emails a month, then the number of clicks will go down.

This means that you are boring. Once that happens, subscribers are more likely to unsubscribe. Where’s your sweet stop - nobody knows.

Test it and see. I know, you have to produce lots of new content.

#6 Bounce Rate

Having an extremely low click rate isn’t good at all, but it can be much better after a few changes. But, having an extremely high bounce rate can be the reason for getting penalized.

Bounce Rate Formula

As you can see in the photo, failing to deliver 6,000 out of 10,000 sent newsletters means that your bounce rate is 60%.

Hard bounce rate by industry

According to SilverPop, a normal bounce rate should be around 0.55%. This also depends on the industry.

For example, Industrial Manufacturing & Utilities companies have the highest bounce rate, while Retail & Ecommerce industry companies have the lowest bounce rate.

Once your subscribers bounce, you must unsubscribe them and remove them from the list. This will also save your costs since email marketing apps always charge per number of subscribers.

Having bounce rate is normal as long as it stays within industry stats. Why do emails bounce? Three main reasons:

  • Subscriber has deleted his email account
  • The domain name doesn’t exist anymore
  • Problems with email servers

However, having a very high bounce rate is actually a good indicator that you have bought the list. Buying the list and sending newsletters to that list is classified as spam and it’s against SPAM ACT.

It's simple - don't send non-permission emails.

#7 Lead-To-Conversion Rate

The purpose of email marketing is to:

  • Establish the brand authority
  • Convert subscribers into customers

Every time you get new subscribers, you should know how many of them you need to convert into customers.  Here’s how to calculate a conversion rate.

Email Conversion Rate Formula

For example, if you send 5,000 subscribers to your landing page, 500 them buy a subscription on your site, it means that 10% of subscribers have converted.

These numbers just came out of my head, but let’s see what studies say. For example, Capterra says that you should be able to convert 7% of your visitors into leads.

Software Conversion Rates

After that, you should be able to convert 36% of leads to qualified opp (more ready to buy), and after that, 27% of qualified opp to sale. You can’t watch this from one angle.

What I’m trying to say is this - once you capture a new subscriber, you should try to get him on the Skype call where you can do the rest. Email marketing leads him to your customer's list.

#8 Delivery Rate

This rate is closely related to the bounce rate. Having too high delivery rate means your bounce rate will be very low and vice versa.

Specifically, having a bounce rate of 5% means that your delivery rate is nearly 95%.

Why do you say nearly and not exactly?

When you send newsletters there’s a small chance that they don’t land in the inbox. Instead, your emails might go to the spam folder.

According to Return Path, just 79% commercial emails land in the inbox. In other words, every five emails sent, one never reaches the intended recipient.

Global Inbox Placement Rates Decline

The same study suggests that some industries have better deliverability. For example, commercial emails in the Technology industry often go to the spam folder.

Inbox vs Spam or Missing

But Health & Beauty industry has the best delivery to the inbox.

It’s impossible to know how many emails went to the spam folder, but you can calculate your delivery rate assuming that all emails are going to the inbox folder.

Having a delivery rate of 100% will never happen, but there are ways of increasing it:

  • Clean the list
  • Buy a dedicated IP address
  • Create a subdomain
  • Authenticate your email properly
  • Avoid using spammy words in subject lines and content

p.s. Don’t buy the list!

#9 Cost per Lead

Do you know much does it cost you to get a new subscriber? Well, the amount depends a lot on the way of acquiring new subscribers.

Facebook Ads and blogs can be your leverages. For me, this is the most important metric because if acquiring new leads costs too much, nothing else makes sense. In that case, open rate, click rate, bounce rate, and other metrics are useless.

Generating leads through Facebook Ads means that you must have enough money to invest in ads. If you wish to see the exact amount of acquiring new leads, you’ll have to install Facebook Pixel on your site.

Facebook Lead Ads

Source: Digital Deepak

Implementing Facebook Pixel is more than measuring how much one lead costs you. It lets you return people who visited your site before, find similar people by using Lookalike Audiences, and so on.

Lots of successful companies use Facebook to generate leads, and Uber is one of them.

Uber lead generation ad

Source: HubSpot

Next, if your blog if the main source of new leads and 10 blog posts captured 1,000 emails, calculating the only one variable matters - time.

Spending 20 hours on producing and promoting a new blog post means that 10 blog posts will take you 200 hours. Having an hourly rate of $30 tells your cost per lead is $6.

Here’s the math.

200 hours x $30 hourly rate = $6,000

$6,000 total cost per lead / 1,000 leads = $6 CPL.

I’d always suggest using the blog as a leverage because it's investing in the future. When you stop advertising on Facebook, you’ll see how increasing the number of leads stops.

However, the best solution is using both, of course. Blogging isn’t only for B2B companies.

B2B companies that blog generate more leads

It’s a fact that B2C companies that blog generate 88% more leads per month than those that don’t.

#10 Email Sharing Rate

Forwards are generated when subscribers find an email interesting enough, so that they want to pass on others.

Return Path has researched sharing/forwarding emails.

Forward rate

It appears that Telecommunication, Insurance, and Utility industries have the highest forward rates. The formula of Sharing Rate is quite simple.

Email Sharing Rate

According to Salesforce, improving this rate is possible with the following actions:

  • Extend the offer to the recipient’s network
  • Replace your CTA with “Forward to a Friend”
  • Use custom social media links

Improve your email forwards

For example, your every newsletter signature could contain something like this:

Share this email with your colleague and help him in learning something new!

For better measuring email campaigns, you should use UTM codes. Using Campaign URL Builder, you can easily measure how many people click on your CTA, for example.

URL Builder

The last field is actually for differentiating your ads. There, you can test different CTA versions and other links as well. The results are available in Google Analytics.

#11 ROI

You probably remember from the beginning of this article that the email marketing channel has the best ROI.

Lots of marketers know that and that’s why they are investing so much in email marketing, and they are usually the most successful. Here’s the formula of ROI.

Overall ROI

For example, if you invest $100 and make $4000 in sales, your overall ROI will be 3,900%.

Overall ROI = $4000 - $100 / $100 × 100 = 3,900%

Keep in mind that you should include total costs of handling newsletters since you have to pay email marketing app unless you have your own system, but if that’s the case, your hosting provider still charges you.

Marketers who don’t understand the importance of email marketing usually think that emails are the past and they should focus on other channels. Here are some additional reasons why email marketing’s ROI is so great:

  • Personalization
  • Segmentation
  • Cost-effectiveness

However, the most important is that when you capture a new subscriber, he’ll be there very very long, as long as he doesn’t unsubscribe or bounce, and most of them won’t do that so fast.


As you can see, there are many important metrics that you have to track. As for me, everything starts from Cost per Lead since you need to know how much does it cost you to get new subscribers.

After that, Lead-to-Conversion Rate appears to be the next important KPI.

Knowing that one lead costs you $10 and 1 in 20 leads become your customers, means that you have to spend $200 on acquiring a new customer. That’s what we call Cost per Acquisition (CPA) and what I didn’t mention here.

Also, I didn’t mention CLV (Customer Lifetime Value) which tells us how much an average customer will pay you until he leaves you.

However, the Lead-to-Conversion rate also depends a lot on your open rate and click rate, so basically, you need to do everything to make sure that as many people as possible visit your link.