The Best Email Marketing Metrics for eCommerce in 2023

The success of an email marketing campaign depends on multiple factors: did your audience read your message? Did they click on the links and buy your products? Or did they unsubscribe from your list?

Email marketing metrics don't just track every inch of a marketing campaign. They're the best tool to evaluate it and show⁠—using cold hard data⁠—if it was a success. 

Email metrics also get down into the nitty-gritty of what your customers think. Metrics show what content customers respond to, if certain emails bring in more revenue and even if campaigns are more successful on mobile devices. 

Here are 12 metrics you should use to track the success of your eCommerce store 👇 

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Why should you use email marketing metrics for eCommerce?

Email marketing metrics are the data that will show you how successful your campaigns are.

But they also give you a greater insight into what content works and what offers, subject lines and products your customers respond to. The main aim of any campaign is usually to boost sales or increase brand awareness, and it’s impossible to know if it’s a success unless you’re tracking and measuring metrics. 

Tracking metrics around engagement and revenue helps marketers see what’s working—and what’s not. These email marketing statistics will prove it.

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The best email marketing metrics for eCommerce

1. Open Rate

What is an Open Rate?

Open rate is a great starting point to get an idea of how your campaign is landing with customers. 

If an email lands in a customer’s inbox and you’ve written a compelling enough subject line (47% of recipients open emails based on this alone), there’s a good chance they’ll read it.

Open rate tracks the percentage of list subscribers who open a specific email during a campaign. This metric shows you if subscribers are receiving your emails and if the content is engaging and effective enough to get them to open it. 

However, email open rate is a broad metric. Even if an email was opened, it doesn't mean the subscriber read it or clicked on anything. Without other metrics, it's impossible to calculate an email's success on open rates alone. 

Good to know: With the recent changes to iOS 15, open rates are no longer totally accurate. You can still use it as a broad metric to track campaigns—but it shouldn’t be the top metric on your list. 

How to use open rates

Open rates should be used to measure how strong brand awareness and marketing messages are. 

They give you a surface-level indication of how successful the hooks and offers in your subject lines are, and if certain copy works better on your target audience than others. 

How to calculate open rate

# of emails opened / # of emails delivered

Example: If you sent 10,000 emails to subscribers and 1,000 were opened, your open rate is 10%.

2. Unique Open Rate

What is Unique Open Rate?

A Unique Open Rate tracks how many times a customer opens a specific email. 

If customers opened an email several times, it could indicate peaked interest in a specific offer or product. 

How to use Unique Open Rates

You may use unique open rates to measure certain emails in a campaign or product launch. 

For example, if you send out a staggered campaign for BFCM and the final email in the sequence is for a last-minute 50% off deal, unique open rate tracks how many customers considered using it. Cross-referenced with other metrics like clickthrough rates, unique open rates measure how many customers ended up using—or ignoring—the odder. 

It's also perfect for A/B testing headlines or offers. For example, using multivariate testing technology, A/B testing measures different sales and product offers to see what lands better with your customers. Sendlane’s multivariate tool allows you to test up to 4 variations on things like CTA, color and images to see which combination drives the most interest and opens for your subscribers. 

How to calculate unique open rates

Total unique opens / total subscribers x 100

Example: If you sent 10,000 emails to subscribers and 2,000 were opened multiple times, your unique open rate is 20%.

3. Click Through Rate

What is click-through rate?

Click-through rate (CTR) measures how many subscribers clicked a link (usually a call-to-action) placed inside your email. 

CTR measures the success of a campaign based on how many customers actually land on your website from a specific email. Click-through rates depend on your industry, but according to recent data from Acoustic, the average CTR for email is around 1.4%. 

How to use click-through rates

Even with a high open rate, your campaign will have limited success if it's not driving customers to the checkout. 

Tracking CTR shows how many customers are willing to take the next step and look at your website instead of clicking back into their inboxes and forgetting about your email. In Sendlane, marketers can get a granular insight into which links for individual emails are performing well and how many of them are gaining unique clicks from subscribers: 

This will give you an idea of whether or not the CTAs in your email are engaging enough (or offering a good enough offer) to drive customers to your site. Be mindful that B2C campaigns usually have a lower CTR than B2B campaigns, which isn't surprising if you consider how many emails are sent to customers daily. 

How to calculate click-through rates

# of all opens / # of all clicks x 100 

Example: If you sent 10,000 emails to subscribers and 200 of them clicked on your CTA, your click-through rate is 2%.

4. Click To Open Rate

What is click to open rate?

Click to Open Rate (CTOR) gives you granular insight into a campaign's CTR. 

It tells you how well your subscribers are engaging with your emails as it tracks unique opens and unique clicks. Combining these metrics can measure if content is connecting with your audience and if it meets their expectations. 

How to use click to open rate

CTOR is a good measure of whether your content, from subject line to CTA, aligns with customer expectations when they first open the email. 

A low CTOR could indicate that the CTA in your email didn't match the subject line. If you were talking about a new product release in your subject line, and then the CTA asked the subscriber to sign up for another offer entirely, this is a mismatch in expectations and will probably result in a lower CTOR. But a high CTOR probably means you delivered on what your subject line and email content promised, and your customers were excited to see what the offer was all about. 

At Sendlane, we think a 10%-15% CTOR is a good benchmark. Anything lower could indicate your messaging is mixed and it's confusing customers. 

How to calculate click to open rate

# unique opens / # unique clicks x 100

Example: If you sent 10,000 emails to subscribers and had 1,000 unique opens and 200 unique clicks, your CTOR is 20%. 

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5. Revenue Per Open

What is revenue per open?

Revenue Per Open measures how many of your customers make it to your checkout after engaging with an email campaign. 

This metric is important as it helps spot which emails (and campaigns) are bringing in paying customers.

How to use Revenue Per Open

Revenue Per Open measures if all of those opens and clicks translate into dollars at the checkout. 

While some email campaigns, like welcome sequences and order confirmations, won't use this metric, measuring others, like holiday campaigns and product launches, is vital to see if your customers are engaging with them. 

Again, a tool like Sendlane will measure Revenue Per Open for you automatically. Inside the dashboard, the revenue generated from each email workflow and campaign is tracked alongside click and open rates so you can measure how successful they are individually. 

How to calculate revenue per open

$ total per campaign / campaign open-rate

Example: If you sent 837 emails to subscribers and had a 39% open rate with $18,256 revenue generated, the Revenue Per Open rate is $56. 

6. Bounce Rate

What is bounce rate?

Bounce rate shows how many of your emails didn’t make it to your subscribers’ inboxes. 

It's a crucial metric to track and measure, as it can pinpoint if subscribers have given a dud email address or if their ISP has blocked you. 

How to use bounce rate

When you track your bounce rate, you can see how many engaged subscribers you have and make removing inactive or spam addresses from your list easier.

While it’s almost impossible to avoid bounced emails, if every campaign has a high percentage, it could mean you have a lot of fake email addresses on your subscriber list or ISPs don’t trust your email delivery tool. If it’s the latter, you need to look at why your emails are bouncing and consider switching to a more trustworthy tool. 

How to calculate bounce rate

# bounced emails / # emails sent x 100

Example: If you sent 10,000 emails to subscribers and 100 emails bounced, your bounce rate is 1%. 

7. Spam Rate

What is spam rate

Don’t confuse Spam Rate with Bounce Rate. 

Emails bouncing is perfectly normal and can be because of an unused email address or a full customer inbox. But an email that’s marked as spam can be because of a customer complaint or your content being flagged by an email service provider (ESP). 

If your emails are continuously marked as spam, ESPs can take action and even block your account from sending emails to its customers. Worse, it can lead to your account being blacklisted and make it hard to send campaigns in the future. 

How to use spam rate

Tracking spam rates can show if your emails abide by rules set by ESPs and if you're meeting customer expectations.

Like bounce rates, it’s nearly impossible for your emails to completely escape spam filters. 

Usually, this is down to innocent mistakes and using the wrong words in your copy. Some ESPs, like Google and Microsoft, have a list of “curse words” that will automatically file your email into a subscriber’s spam folder if you use them. Hint: using $$$ or 100% Free! in your subject line is a quick way to have a campaign sent straight to spam. 

That said, it's easy to avoid the spam filter by following a couple of best practices. Avoid using curse words (check out our guide here) and give customers a way to easily unsubscribe from your list if they want to. 

How to calculate spam rate

# spam complaints / emails sent x 100 

Example: If you sent 10,000 emails and 10 of them were marked as spam, your spam rate is 0.1%

8. Unsubscribe Rate

What is unsubscribe rate

Unsubscribe rate tracks how many of your customers are opting out of receiving your emails. 

The harsh reality is that some customers will always unsubscribe from your list. They may have purchased something from your site for a family member over the holidays (and don't intend on shopping with you again), or they may not be getting value from your emails anymore. 

How to use unsubscribe rate

Depending on your industry and unsubscribe rate, this metric will show you a usual up-and-down cycle of an eCommerce brand, or point to something more sinister, like generic campaigns that aren’t engaging with your audience. 

Customers unsubscribing to your emails isn't always a bad thing. If they don't plan to buy anything from you again, there's no reason to send them unique offers or news about your products. However, if customers are unsubscribing because they're not finding value in your content, it could mean you're not putting in enough effort on the segmentation and personalization front. 

Again, your ESP will track your unsubscribe rate to help you spot any worrying patterns. Inside the Sendlane dashboard, you can view unsubscribe rates within individual campaigns to see if people are opting out during certain emails, or if the rate holds steady at a certain percentage—which is a healthy, perfectly normal pattern for eCom brands. 

How to calculate unsubscribe rate

# emails delivered / # unsubscribes x 100

Example: If you sent 10,000 emails to subscribers and 200 customers opted-out, your unsubscribe rate is 2%. 

9. ROI

What is ROI?

ROI evaluates how effective your campaigns are and if the money you’ve spent building them is worth the investment. 

While email has the highest ROI out of any digital marketing strategy (it even had a boost with open rates and engagement during the pandemic) campaigns can also be expensive to build. Investing in strategies such as influencer marketing or paid advertising can quickly add up. Even successful campaigns could have a low ROI if the advertising budget outweighed what customers spent. 

Tracking revenue and overall success help marketers pinpoint which campaign tactics work and bring customers to the checkout. 

How to use ROI

ROI is like getting a receipt at the end of a grocery shopping trip.

It shows you exactly what you spent and what you got in return. In email marketing, ROI will show you how much money customers spent during a particular campaign (or even on individual emails) to help you see if the investment you put into the campaign made any money. Usually, ROI is narrowed down to something like: for every $ spent on marketing/distribution/influencers, the campaign earned $ back. 

The ROI that can be harder to track is non-revenue based, like brand awareness or building trust. Campaigns focused on this still bring a ton of value to your brand, but it’s harder to put a hard dollar figure on them once they wrap up. 

How to calculate ROI

$ in campaign sales / $ spent creating the campaign x 100

Example: If you earned $50,000 in sales and the campaign cost $10,000 to create, the overall ROI would be 500%. 

10. List growth

What is list growth?

Are more customers (and potential customers) signing up to your email list?

Tracking list growth will tell you. It will show you if your email content and marketing campaigns are hitting the mark. List growth should also be measured against your unsubscribe rate—while a 5% growth rate is fantastic, if your unsubscribe rate is higher, your list is actually shrinking. 

How to use list growth

List growth measures how well engagement campaigns are hitting your audience. A pop-up on your website offering a discount or opting-in for VIP content are great ways to grow your list, but list growth will tell you exactly how successful these tactics are. 

How to calculate List growth

# of new subscribers - # of unsubscribes / total list # x 100

Example: You have 10,000 new subscribers this month, taking it to a total of 80,000 subscribers. However, 150 people have unsubscribed from your list this month. Your list growth rate is 10,000 – 100 / 80,000 x 100 = 12.37%. 

11. Unsubscribe to Action (UTA)

What is UTA?

UTA (unsubscribe to action) measures your unsubscribes and spam complaints against campaign clicks. 

How to use UTA

Tracking this will give you a clear idea of how well your email performed in terms of engagement and customer satisfaction. 

For example, a low click rate on an email;'s unsubscribe button can mean your email hits the mark with customer expectations and engagement. But a high click rate driving people to opt out could result from a lack of personalization or segmentation during your email campaign. 

How to calculate UTA

# unsubscribes + # complaints / # unsubscribes + # complaints + # clicks

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12. Mobile open rate 

What is Mobile open rate

The final rate you should be measuring is mobile open rate, which tracks how many people on your list open emails on mobile devices and tablets. 

Not only do people prefer to look at emails on a mobile device compared to a desktop (about 85% of us now check email on our phones), emails are opened 3x more by mobile users. 

How to use mobile open rate 

Tracking mobile click rate helps you see how engaging and responsive email campaigns are on mobile devices, and whether customers are shopping on their mobiles. Suppose you have a lot of customers buying products from their smartphones. In that case, you can adapt landing pages and campaigns to be more mobile-friendly and offer easier checkout options, like integrated mobile payment options, to give them a better shopping experience. 

How to calculate mobile open rate 

# emails opened on mobile devices /# of mobile recipients

Example: Your campaign had 10,000 opens on mobile devices, and 20,000 of your subscribers are mobile recipients. Your mobile open rate is 50%.  

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How to measure email marketing metrics with Sendlane

Email marketing metrics help you measure whether or not your campaigns are hitting the mark with customers.

A campaign's effectiveness can be determined by tracking how many opened or clicked and if they drive customers to the checkout. Measured individually, metrics like click rates, revenue per click and unsubscribe rates will give you snippets of how well a campaign is doing. Bundle those metrics together, and you get a clear picture of how effective your marketing efforts are and how engaged your customers are.

With the right tools, measuring email marketing metrics is easy. Using Sendlane, your data and analytics are readily available at a glance! You can track everything from open and click rates and customer spending to spam complaints and list growth. Sendlane’s complete eCommerce marketing platform does the hard work for you so you can get back to what you do best—creating marketing campaigns and selling products. 

Want to take Sendlane for a test drive? Sign up for a free trial here. 

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Email marketing metrics FAQs