E-commerce KPIs: Conversion, AOV, Repeat Rate and More
The e-commerce KPIs that drive online store profit: conversion rate, AOV, repeat rate, CAC and more, with formulas and a worked rand example for a small shop.
· 4 min read · Summarix team
Online store revenue comes down to one equation: revenue = sessions × conversion rate × average order value (AOV). The e-commerce KPIs worth tracking either move one of those three levers or tell you whether the resulting revenue is profitable. This guide gives you the formulas, a worked example and what to do when each number moves.
The core e-commerce KPIs
| KPI | Formula |
|---|---|
| Conversion rate | Orders ÷ sessions × 100 |
| Average order value (AOV) | Revenue ÷ orders |
| Revenue per session | Revenue ÷ sessions (or conversion rate × AOV) |
| Cart abandonment rate | (Carts created − orders) ÷ carts created × 100 |
| Repeat customer rate | Customers with 2+ orders ÷ total customers × 100 |
| Purchase frequency | Orders ÷ unique customers (over a period) |
| Customer acquisition cost (CAC) | Marketing spend ÷ new customers |
| Customer lifetime value (LTV) | AOV × purchase frequency × gross margin % × expected customer lifespan (periods) |
| Return rate | Items returned ÷ items sold × 100 |
| Contribution margin per order | AOV − product cost − shipping − payment fees − packaging |
Worked example: a month in a small online store
Say your store had 25,000 sessions in August, took 500 orders and made R325,000 in revenue. 380 of those orders came from new customers, and you spent R38,000 on ads. Product cost averages 50% of the selling price, shipping costs you R80 an order and payment fees are about 3%.
- Conversion rate: 500 ÷ 25,000 = 2.0%
- AOV: R325,000 ÷ 500 = R650
- Revenue per session: R325,000 ÷ 25,000 = R13
- CAC: R38,000 ÷ 380 = R100
- Contribution per order: R650 − R325 (product) − R80 (shipping) − R19.50 (fees) = R225.50
Now the useful part. At R100 CAC and R225.50 contribution, each new customer is profitable on the first order, before any repeat purchase. If CAC crept up to R250, first orders would lose money and the business would depend on customers coming back. That is why AOV, CAC and repeat rate must be read together.
Conversion rate: what moves it
Conversion rate varies widely by product, price point and traffic source, so compare yourself with your own history rather than a generic benchmark. Break it down by device and by traffic source: a store converting well on desktop but poorly on mobile has a mobile checkout problem, not a marketing problem.
- Slow pages, especially on mobile data, reduce conversion.
- Unexpected costs at checkout (shipping revealed late) drive cart abandonment.
- Few payment options can lose buyers at the last step. Local shoppers often expect card, instant EFT and similar options.
- Weak product pages (poor photos, no sizing, no delivery estimate) lose people before the cart.
AOV: raising it without discounting
AOV rises with bundles, ‘frequently bought together’ suggestions and a free-shipping threshold set a little above your current AOV. If AOV is R650, a free-shipping threshold of R750 nudges people to add one more item. Watch contribution margin at the same time: free shipping that raises AOV by R50 but costs R80 a parcel is a loss.
Repeat rate and LTV: where profit lives
Returning customers do not cost you another R100 to acquire. Continuing the example: if customers order on average 2.5 times over two years at R650 AOV and a 50% product margin, LTV on gross margin is R650 × 2.5 × 0.5 = R812.50. With a R100 CAC, the LTV:CAC ratio is about 8:1, which leaves room to spend more on acquisition if you want to grow faster.
Track repeat rate by cohort: of the customers who first bought in January, how many had bought again by April? Cohort views stop a big acquisition month from making repeat rate look artificially low. More on this in marketing KPIs: ROI, CAC and ROAS.
Connect Shopify or WooCommerce and Summarix turns your orders into a KPI report with conversion, AOV, repeat rate and a plain-English summary.
Free plan: 5 AI reports a month, no card needed.
Building a simple e-commerce dashboard
- Top line: revenue, orders, conversion rate, AOV, compared with last month and last year.
- Acquisition: sessions and new customers by channel, CAC by channel.
- Retention: repeat customer rate and cohort repeat rate.
- Profitability: contribution margin per order and return rate.
- Notes: promotions, stock problems, courier delays or outages that explain unusual numbers.
If you sell on Shopify or WooCommerce, Summarix can connect to your store, compute these KPIs from your order data and write the monthly narrative. Our guides to Shopify sales reports and South African e-commerce reporting cover the platform-specific details.
Conclusion
E-commerce KPIs make sense when you connect them: traffic times conversion times AOV gives revenue, and contribution margin, CAC and repeat rate tell you whether that revenue is worth having. Track them monthly, break them down by channel and device, and you will know exactly which lever to pull next.
Frequently asked questions
What is a good conversion rate for an online store?
It depends heavily on your product, price and traffic source, so the most useful benchmark is your own trend. Focus on improving it month on month and comparing it by device and channel.
How do you calculate average order value?
Divide total revenue by the number of orders for the same period. Exclude refunds consistently, or include them consistently, so months remain comparable.
What is the difference between repeat customer rate and retention rate?
Repeat customer rate is the share of customers who have bought more than once. Retention rate usually measures how many customers from a starting group are still buying in a later period.
Which e-commerce KPI matters most?
Contribution margin per order combined with CAC, because together they show whether growth is profitable. Revenue alone can grow while the business loses money.