10 Key eCommerce Metrics to Measure for User Engagement

To increase user engagement in an online store, measure 10 core eCommerce metrics: average views per session, conversion rate, cart abandonment rate, checkout abandonment rate, average order value, retention rate, customer lifetime value, gross margin, cost per acquisition and return on ad spend. Together they show how visitors behave on your site, where they drop out of a purchase, whether they come back, and what that engagement costs you.

Keeping track of the right eCommerce metrics is paramount if you want to keep your customers engaged. Yet, it's easy to get lost in countless metrics, KPIs and formulas. That's why we've gathered the core eCommerce metrics that will help you improve your product offering, service and engagement with customers. For the broader set of business KPIs, see our guide to important eCommerce metrics.

What should you do before you start measuring KPIs?

It's crucial to develop a viable strategy for measuring key performance indicators. This includes identifying and prioritizing your short-term and long-term goals. You also need to state the main objectives you're aiming to achieve and set up an eCommerce metrics dashboard where the numbers live side by side.

Keep the dashboard focused. In a 2004 Harvard Business School Working Knowledge article, Start to Measure Your E-commerce Success, Marc J. Epstein recommends combining financial and non-financial measures and warns against tracking too many: roughly three to six measures per element, and no more than twenty in total. The 10 metrics below fit well within that limit.

How does Google Analytics 4 measure engagement?

Many older guides to engagement metrics were written for Universal Analytics, which Google replaced with Google Analytics 4 (GA4). Some metric names and definitions changed, and a few changed meaning completely. According to Google's help page on engagement rate and bounce rate, an engaged session is one that lasts longer than 10 seconds, has a key event, or has 2 or more screen or page views. The 10-second timer is a default: you can raise it to up to 60 seconds in your web data stream settings.

With that in mind, here's our list of the 10 core eCommerce metrics for increasing user engagement, grouped by the question each one answers.

Which metrics show how visitors engage with your site?

1. Average views per session

Page views is one of the core metrics: the number of times a particular page has been viewed by visitors. Average views per session (called pages per session in Universal Analytics, and average page views per visit in older reports) shows how many pages a visitor views in a typical visit.

Measuring it helps you understand how people move through your website and how they engage with different pages. It is best for spotting navigation problems. A high number can mean visitors are exploring your catalog, but it can also indicate that they are traveling through your website failing to find the information they need.

For example, 60,000 page views across 15,000 sessions gives 4 views per session.

2. Conversion rate

The conversion rate is the percentage of users who complete the desired action you want them to perform. These actions vary with your objectives and can range from subscribing to your email list to completing a purchase after visiting your website or viewing a particular product page. In GA4, the actions you track are key events.

Conversion rate is particularly important if you're running multiple eCommerce digital marketing campaigns. Measuring it by channel lets you identify which channels bring users who engage and convert better than others.

All of the following formulas are valid. The choice depends on your definition of a conversion event and how you measure website traffic, so pick one and use it consistently:

For example, 450 orders from 15,000 sessions is a conversion rate of (450 ÷ 15,000) × 100 = 3%. To judge your own number, see what a good eCommerce conversion rate is.

Which metrics show where shoppers drop out of a purchase?

3. Cart abandonment rate

The shopping cart abandonment rate is the percentage of customers who add items to their shopping carts, then abandon their carts without completing a purchase. It is a crucial eCommerce metric because it shows how many customers intend to buy products but never complete their purchase.

When it comes to cart abandonment, the value of the items added to the cart, the number of items and the shipping time all matter. By comparing this rate with other metrics, you can build a strategy to increase engagement and lower abandonment.

For example, if 1,000 shoppers add items to their cart and 300 complete a purchase, the cart abandonment rate is (1 − 300 ÷ 1,000) × 100 = 70%.

4. Checkout abandonment rate

The checkout abandonment rate is the percentage of customers who start checkout and then abandon the purchase.

Even though checkout abandonment is similar to cart abandonment, the two should not be confused. Customers who abandon during checkout are one step further along than customers who abandon their carts. This metric gives you specific data about incomplete transactions after customers have shown clear interest in buying, so it is best for finding friction in the checkout itself: forms, payment options, account creation or unexpected costs. Analyze it to develop strategies for a better user experience.

For example, 300 completed orders from 400 started checkouts gives (1 − 300 ÷ 400) × 100 = 25%.

5. Average order value

Average order value (AOV) is the monetary value of an average customer order on your website. Its counterpart, average abandoned order value (AAOV), is the average value of the orders that customers abandoned in the cart or during checkout.

Keeping track of both AOV and AAOV helps you understand engagement at the moment of purchase. You want to know which elements encourage customers to complete a purchase and, on the other hand, which make them abandon their orders. If abandoned orders are much larger than completed ones, shipping thresholds or price anxiety on large baskets are worth investigating.

For example, $36,000 of revenue from 450 orders gives an AOV of $80.

Which metrics show whether engaged customers come back?

6. Retention rate

The customer retention rate is the percentage of existing customers who keep buying from you over a given period.

Keeping track of the retention rate gives you a better idea of the longevity of your eCommerce business. It also helps you figure out why customers return to make another purchase, and it is the clearest sign that engagement lasts beyond a single visit.

For example, if you start the quarter with 2,000 customers, acquire 500 new ones and end with 2,100, your retention rate is ((2,100 − 500) ÷ 2,000) × 100 = 80%. Subtracting new customers matters: without it, strong acquisition can hide the loss of existing customers.

7. Customer lifetime value

Customer lifetime value (CLV or CLTV) is a prediction of the value of your future relationship with a customer. To put it simply, it's the amount a customer is expected to spend on your products during their lifetime as your customer.

CLV is a key metric because it shows how much your customers are worth to you on average. Use it to tell apart the customers who are economically more valuable to you and to decide how much you can afford to spend to keep them engaged.

To calculate customer lifetime value, first calculate lifetime value (LTV), which is based on revenue:

For example, a customer who spends $80 per order, places 3 orders a year and stays for 2 years has an LTV of $80 × 3 × 2 = $480. At a 25% profit margin, their CLV is $480 × 0.25 = $120. Nexus by Omniconvert calculates CLV and RFM segments from your order data, so you can see which customers are worth the most effort.

8. Gross margin

Gross margin is the share of sales revenue you keep after paying for the goods you sold. In other words, it shows how much you actually earn on each sale before other operating costs.

Understanding how much you earn per sale matters for engagement too: discounts and free shipping can raise conversion rate and engagement while quietly eroding margin. Track gross margin to make sure your eCommerce business is scaling properly, not only growing.

For example, $36,000 of revenue with $21,600 cost of goods sold gives ((36,000 − 21,600) ÷ 36,000) × 100 = 40%.

Which metrics show what engagement costs you?

9. Cost per acquisition

Cost per acquisition (CPA) is the amount of money you have to spend to gain a new customer (for an academic view of eCommerce success measures, see Ghandour, Deans, Benwell and Pillai, Measuring eCommerce Website Success, ACIS 2008). Cost per acquisition can include:

• Email campaign costs
• Advertising costs
• Discount offers, and anything else it took to make the sale

Keeping track of CPA gives you perspective on how much cost and effort you spend to engage and acquire new customers. Compare it with CLV: a customer who costs more to acquire than they are worth is not a growth engine.

For example, $9,000 of ad spend that brings 300 new customers gives a CPA of $30.

10. Return on ad spend

Return on ad spend (ROAS) closes our list. ROAS is the revenue generated by a specific advertising channel or campaign for every unit of money spent on it.

Keeping track of ROAS helps you see how much advertising it takes to engage users and get them to complete a purchase. You can use the results to identify the most effective advertising channels and improve the rest accordingly.

For example, $36,000 of revenue from $9,000 of ad spend is a ROAS of 4, often written as 4:1 or 400% (multiply by 100 for the percentage).

What are the formulas for all 10 metrics?

How often should you measure eCommerce metrics?

How often should you measure eCommerce metrics? Some metrics should be checked weekly or bi-weekly. Others require a longer data window and should be measured monthly or quarterly. So the best answer is that eCommerce metrics should be tracked consistently. The persistent growth of an online store comes from regular performance analysis over time.

• Weekly or every two weeks: views per session, conversion rate, cart and checkout abandonment rates, cost per acquisition and return on ad spend. These move quickly and react to campaigns and site changes.
• Monthly or quarterly: average order value, retention rate, customer lifetime value and gross margin. These need more orders and more time before a change is meaningful.

When a metric moves, turn it into a test rather than a guess:

1. Spot the change

   Compare the metric with its usual range and with the metrics around it, for example checkout abandonment against average order value.
2. Find the cause

   Segment by channel, device and page, and ask visitors directly with an on-site survey.
3. Form a hypothesis

   Write down what you will change, which metric it should move and why.
4. Test it

   Run an A/B test so you know the change, not the season or a campaign, moved the metric.

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