The Art of eCommThe
Retention Calculator
Discover how many dollars a year Leaky Retention is costing you, with simple math!
The collection
The playbook behind:
The same retention work runs underneath every brand here.
Start here
The era of cheap, endless customers is over
For years, eCommerce ran on one assumption: there is always another cheap customer to buy. Spend on ads, win the order, repeat. Growth on tap.
That party is over. Tariffs, rising CAC, shaky consumer confidence, a looming recession. Here at The Art of eComm, we call it the Mow-Your-Own-Lawn era, where every brand is suddenly asking what it can trim and what it can survive on.
Here is the trap nobody is aware of. A brand built only on new buyers is a leaky bucket. The tables are full, but nobody comes back. If acquisition gets expensive, brands fall into survival mode overnight.
The only way to survive and thrive in the Mow-Your-Own-Lawn era is through Retention. Getting the customer to come back, again and again, is what turns a leaky bucket into a business that compounds.
I created this playbook to show you:
- The Retention Debt Calculator, that reveals how many dollars are leaking out every year
- The 2 numbers that tell you if you're actually winning: RCM and OCAS
- Where your brand ranks on the RCM Pyramid, from Rust to Gold
- The single lever that moves you up the RCM Pyramid: your 30-Day Repurchase Rate.
Where the money is
Acquisition gets you the customer. Retention gets you paid.
To get new customers for any eCommerce brand on Earth, you need to spend money on ads. And between the discount that pulls them in, the COGS, and thin margins, that first order barely makes you your money back.
The second order and beyond is where the real profit starts, money actually in the bank. A returning customer costs nothing to win again, so every order after the first carries even more margin.
So when a brand pours more into ads while buyers leave after one order, it is not growing. It is filling a leaky bucket faster, and tipping closer to survival mode.
That is why I built this playbook: to show you what leaky retention is costing you, before it's too late.
The Retention Debt Calculator later inside this Playbook only means something once you understand 2 metrics: RCM & OCAS.
Unless you've already read Retention Economics by Thomas Lalas, the founder of The Art of eComm, in which case you're familiar with both, read the following 2 masterclasses very carefully.
Before you calculate
Masterclass on Retention Economics, Part 1: RCM
Revenue is a vanity number. You can post a record month and still lose cash on every order once you count the goods and what you paid to acquire the buyer.
So we grade brands on RCM, their Retention Contribution Margin:
RCM = Net Revenue − COGS − CAC
It is the cash your customers actually leave behind after you have paid to make the product and to win them over.
A low RCM means your growth is borrowed, and the brand cannot lead its category until retention improves.
A high RCM means the business funds itself, steals share, and pays its founders.
RCM is only half the story though. On to Part 2.
Before you calculate
Masterclass on Retention Economics, Part 2: OCAS
In reality, RCM is half the picture.
For a subscription brand, every month has 2 jobs: pay the bills today, and buy the growth for tomorrow. OCAS is what both cost together, your Operating Expenses, plus next month's CAC, plus three months of stock.
OCAS = OpEx + Next Month's CAC + 3 Months of Stock
Now hold the two numbers against each other. This is the Law of Retention Economics:
If RCM ≥ OCAS, compound, self-funded growth is inevitable.
Clear OCAS with your RCM and your customers fund the entire machine, no outside money needed. Fall short, and the difference comes from your pocket, a loan, or dilution.
Hold both numbers in your head, because the Retention Debt Calculator is about to rank your brand on these 2 metrics.
In one click you get 2 things:
Your placement on the RCM Pyramid, and your Retention Debt, the money you're missing out on because of Leaky Retention.
Grade your retention
The Retention Debt Calculator
This is the moment.
Grab last month's P&L and your Shopify cohort data, and drop the numbers in.
In one click you get three things: your RCM, the OCAS it has to clear, and your Retention Debt, the dollars leaking out every year.
(The fields are pre-filled with an example so you can see how it reads. Replace them with your own.)
RCM = Net Revenue − COGS − CAC. OCAS = Operating Expenses + Next Month's CAC + 3 Months of Stock.
The full ladder
All five grades of the RCM Pyramid
That grade you just got places you on the RCM Pyramid, the same ladder we use to rank brands from Rust to Gold.
Where you land is set by how much of your OCAS your RCM can cover.
Climb, and your customers fund more of the business. Slide, and you fund more of it out of your own pocket.
Your tier is a snapshot from a single month, so it can move either way fast. Tap any tier to see what it means.
What the numbers are telling you
The real lever to pull: your 30-Day Repurchase Rate
Your tier comes from your RCM, and your RCM comes from one thing: how fast customers come back.
The metric doing the work is your 30-Day Repurchase Rate, the share of first-time buyers who place a second order within 30 days.
Moving a customer from order 1 to order 2 is the billion-dollar question.
Practically, a 30-Day Repurchase Rate below 60% is a problem. 60 to 69% is sustainable. Above 70% is where compounding takes over.
For example, if your blended CAC is $91 and a first order recovers $60, you start under water. The moment that customer comes back and spends another $60, you are in profit. Let the second order drag past 120 days and your profit freezes in cohorts that never pay you back.
The Retention Debt the calculator showed you is the gap between your repurchase rate today and a healthy one. That is real money, leaving every year, that belongs in your business.
Where the climb starts
Ghosting your customers in the first 30 days??
The repurchase rate is won or lost in the first 30 days after the first order ships.
The single biggest mistake a brand can make after a customer purchases is to go into incognito mode, and completely ghost the customer for the next 30 days.
It is during these 30 days that a buyer either forms the habit of using the product and comes back for more, or forgets you completely.
How do you really improve the 30-Day Repurchase Rate though?
- Rebuild the customer's Post-Purchase Experience with transparency, upsells, cross-sells, education, and habit-forming content.
- Move one-time buyers onto subscription, where their lifetime value runs two to five times higher than a single purchase.
- Include freebies in the subscription journey, and reframe the billing reminder from "You're paying in 3 days" to "your next freebie is arriving".
Above 70% 30-Day Repurchase Rate, the math compounds on its own.
This month's margin buys next month's customers, who fund the month after. That is the engine running underneath every brand at the top of this page, and the way out of survival mode for good.
The next step
See how this applies to your business
Congratulations! You just graded your brand on the RCM Pyramid!
The next steps are looking into your deeper numbers, like your Full Retention Curve, your LTV/CAC Ratio, and coming up with a proper 30-day post-purchase experience for your subscribers.