Picture this:
I have an e-commerce brand with a goal of hitting $5,000,000 in revenue this year.
A part of this objective is improving my email marketing strategy, but I’m not sure how to measure its impact.
Which email metrics would you tell me to track and improve? Which ones should I definitely ignore?
Seriously, take a moment to think about it.
Your answer will tell me everything I need to know about your mindset.
If you start by mentioning metrics like growing the email list to a certain number of subscribers and increasing open rates, I know you’re a bit of an amateur.
Amateurs care about vanity metrics while pros focus on high-level growth.
Boosting channel revenue? You’re probably more worried about taking credit than actually helping the business.
Why should I care if I doubled my email revenue but my business didn’t actually grow?
If you had an owner’s mindset — ran email as if you owned the brand, every decision you make would be around achieving profitable growth.
You’d make sure email turns one-time customers into a second, third, fourth-time buyers — without killing profit margins.
Because that’s what email marketing is all about — increasing customer retention.
The 40/40/20 approach to measuring email performance
To measure email marketing success in 2025, I recommend taking a 40/40/20 approach:
• Ignore 40% of the vanity metrics.
• Monitor 40% of the standard metrics.
• Focus on the 20% metrics that drive business growth.
Want more email inspiration? Check out:
25+ Fashion Welcome Email Examples To Convert New Subscribers (2025)
Klaviyo Audit Checklist: 66+ Email Marketing Questions (2025)
105+ Ecommerce Email Examples: 2025 Fast-Growth Brands
Email marketing metrics you should ignore
Open rate
When someone likes your post on social media, it feels good. On the surface, it seems like people are engaging with your content. The problem is that this often doesn’t translate to sales.
Open rates are very similar to social media likes. Just because someone opens your email doesn’t mean they will buy from you. It doesn’t even mean they’ll read your email.
When you stop obsessing over miniature things such as likes and open rates, and put more effort into crafting great email content, you won’t have to worry about open rates ever again.
People on your list will receive an email from you and open it anyway. It’s not because the email has a killer subject line; it’s because it has your brand name attached to it, and they’re used to receiving great content from you.
Unsubscribe rate
Almost every time I tell a client, “You should send more emails,” they respond with something along the lines of:
“I’m worried people will unsubscribe.”
And yes, people WILL unsubscribe, but you’ll also make more money by sending more emails.
Imagine you have to run an email promotion around a new product.
Now, tell me which email campaign results you’d prefer:
Campaign A:
Revenue: $17,023
Emails sent: 5
Unsubscribes: 34
Campaign B:
Revenue: $7,023
Emails sent: 2
Unsubscribes: 12
Would you be angry if you made an extra $10,000 in revenue but lost 22 more email subscribers along the way?
My guess is no, you wouldn’t be.
Unsubscribes are actually a good thing, for a few reasons:
Reason #1: People who unsubscribed weren’t buyers anyway.
They’re just contacts who cost extra money to email.
Reason #2: You get to clean your list for free.
When someone unsubscribes, they take the burden of removing themselves from your list away from you.
Reason #3: Unsubscribes mean people are noticing your emails.
High unsubscribe rates show people are seeing (and interacting) with your emails.
If you’re afraid to send promotional emails to your list or push a sale, remember that unsubscribers are a completely normal (and good) part of email marketing.
List size
Okay, hear me out. Yes, you DO need to grow your email list. Without a list, you won’t make any money because you don’t have anyone to send emails to.
That said, the size of your email list is a vastly overrated metric.
A brand with 100,000 freebie-seeking subscribers can make less money from email than a brand with 5,000 highly engaged subscribers.
When it comes to subscribers, focus on quality over quantity.
Conversion rate
Email marketing is all about context. The conversion rate of a single email campaign depends on dozens of variables.
For instance, a “last chance to buy” email to end a promotion will convert a lot better than an average email campaign.
People who just joined your list are much more likely to engage with your emails than those who joined 6 months ago (that’s why welcome emails have such high conversion rates).
Cart abandonment emails often convert 10x better than post-purchase emails.
See where I’m going with this?
There’s no single “good” or “bad” conversion rate to depend on, so just ignore it.
Email marketing metrics worth keeping an eye on
Click rate
Many email marketers will tell you that their number one objective is to get people to click. Emails are there to “sell the click,” is what they say.
Kat Garcia has a great take on this.
She says you don’t want to chase clicks just for the sake of clicks.
You want people to click on your email because they’re ready to take action.
Remember, high click rates don’t pay the bills. Revenue does.
That said, the more people click on your email, the higher your chances of landing a sale.
Spam rate
Spam complaints are kinda like unsubscribes — receive one, and you know people are interacting with your emails, which is a good thing.
However, unlike unsubscribe rates, spam rates have a much higher impact on your deliverability. You want your emails to keep landing in the right inbox, and that’s a valid enough reason why it’s a metric worth monitoring.
Also, if you have high spam rates, it’s not a deliverability issue, it just means your email marketing strategy sucks.
Bounce rate
This email metric tells you the percentage of subscribers who didn’t receive your email for one reason or another. Again, is it the most important thing in the world? No, but it does have an impact on your deliverability.
If you notice higher than normal bounce rates, it’s probably worth “popping the hood” and taking a closer look. What you’ll often find is that high bounce rates are caused by faulty email addresses which you can remove.
To check your deliverability score, including bounce rates in Klaviyo, go to Analytics → Deliverability.
List growth rate
Chances are if you’re marketing an e-commerce brand, you have some sort of pop-up form on your website. You should aim to optimize your form without cutting too much into your profit margins.
It might take a few tests to find out which opt-in format and incentive works best for your brand, but as long as your list is growing without destroying too much of the value, you’re good to go.
The best metrics to measure email marketing performance
Revenue per subscriber
One of the first things I do when auditing an email account is calculate the revenue per subscriber.
To do this, just take the total revenue generated from email and divide it by the number of subscribers on your list.
Now, I know what you’re thinking…
“What’s considered a good revenue per subscriber?”
And the answer is it depends.
It depends on your industry, your AOV, your product category, the buying cycle, your email frequency, and much more.
It’s not a perfect metric by any means.
But it does give you a health check of your email list.
Another downside to measuring channel revenue is that it’s heavily influenced by your attribution settings. Last-click attribution will almost always produce inflated results.
That’s why I recommend using strict attribution settings in Klaviyo (or whatever your ESP is). I wouldn’t attribute any sales to just “opened” emails.
Retention rate
For most e-commerce brands, email is the main (and only) retention strategy there is.
That’s why the goal of your email marketing program should be to increase customer retention (duh!).
Now, the thing is: most e-commerce businesses can only retain about 30% of customers. The figure is even lower if you’re selling fashion or long lifespan products.
If you can increase your retention rate — for example, by designing a highly converting post-purchase sequence — that’s already a tangible win.
But there is a way to take it a notch further.
Not all your retention comes from email marketing. If you stopped sending emails, a percentage of customers would STILL return for a second purchase.
So the real question becomes:
How much of your customer retention is actually driven by email, and how much would’ve happened anyway?
The only way to measure this would be to find out your baseline retention rate (percentage of people who buy from you again without any marketing) and compare it to your retention rate after emails.
Alexandra Greifeld has a great piece on this, which I recommend reading.
There’s no easy or quick way to do this. And to be honest, if you’re a smaller brand, it’s probably not worth your time.
What’s next?
Now you know that measuring email marketing goes much deeper than tracking open rates, click rates, or even attributed channel revenue.
Use this knowledge to hit your revenue goals.
Best of luck!
