Rising CAC gets blamed for almost every growth problem in ecommerce. But CAC is rarely the problem. It is usually the result of one.
Most ecommerce brands assume rising CAC means one of three things.
- The ads are getting less efficient.
- The targeting is off.
- The platforms are getting worse.
So the response is always the same;
- Tighten the targeting.
- Test new creatives.
- Cut the budget on what’s not working.
- Bring in a new media buyer or ad agency.
And sometimes, for a while, it helps. So let’s throw the following question into the old growth mixing pot;
What if your CAC isn’t broken? What if your model is?
Harsh. I know. But somebody needs to be asking this question. It’s usually me (as diplomatically as I can).
CAC doesn’t break on its own. Something upstream of it is producing the number you’re looking at.
CAC Is an Output, Not a Lever
This is the most important reframe in this article, so let’s be honest about it. CAC is not something you set (oh boy, you wish you could though!). It is something your growth system produces. It’s an output.
It is the result of who you attract, how well you convert them, how much they spend, and how often they come back. Every part of that chain shapes the number that appears in your dashboard.
Traffic quality. Conversion strength. Average order value. Retention rate. These are the variables that you can control to certain extent. That’s your job. CAC,however, that’s the output.
When founders say “we need to lower our CAC”, they are usually identifying the symptom and calling it the diagnosis. The number is telling you something is off upstream. The question is: where?
The Real Problem: You’re Misunderstanding Customer Value
So where do most internal CAC conversations go wrong? Brands set a CAC target. And it’s usually an advantageous target. They optimise to hit it. They report on it. And somewhere in that process, they forget what the number is actually supposed to represent.
CAC only makes sense in relation to what a customer is worth. Not at the point of first purchase. Over time.
A customer who buys once is a transaction. A customer who buys again is a relationship. A customer who buys repeatedly, refers others, and stays loyal over years is an asset.
Most CAC targets treat all three as if they’re the same person. They’re 100% absolutely not.
And if your acquisition strategy doesn’t distinguish between them?
You have a customer value problem wearing a CAC costume.
You don’t have a CAC target problem. You have a customer value problem.
So let’s discuss your Ideal Customer vs Poor-Fit Customer and let’s make this concrete.
Two customers. Both acquired at the same cost. Both make a first purchase.
The first is high intent. They researched before they arrived. They have a strong product fit. They spend more on the first order, return within 60 days, and go on to buy several times over the next two years.
The second is curiosity-driven. They clicked an ad at the right moment. The product was okay. The price was the deciding factor. They don’t come back. They may not even have been the right person for what you sell.
Same CAC on the spreadsheet. Completely different outcome for your business.
The first customer pays back quickly and compounds in value.
The second costs you money when you account for fulfillment, service, and the margin you gave away to win them.
If your acquisition strategy is attracting the second type more than the first, your CAC will always look broken. Because the machine you’re managing is producing the wrong customers.
| Can you answer the following questions (rephrase; you need to be able to answer the following questions…) Who are your most profitable customers? What did they have in common before they bought? What is the AOV and repeat rate of customers from your top-performing ad campaigns vs your broadest campaigns? If you segmented your customer base by LTV quartile, what percentage of your CAC budget is going after the bottom two quartiles? |
The Dangerous Assumption: Lower CAC Equals Better Performance
This one needs to be said directly, because it’s costing brands a lot of money.
Lower CAC does not mean better performance. In many cases, it means the opposite.
You can lower CAC by going broader. Wider audiences. Less restrictive targeting. More volume. The cost per click falls. The cost per acquisition falls. The headline number looks better.
I can get you super low CAC all day long. I’ll just focus on existing customers and low-funnel acquisition.
But broader usually means less qualified. Less qualified means lower intent. Lower intent means worse conversion, lower AOV, and weaker retention.
You have cheapened the number by diluting the quality of what the number represents.
A higher CAC for the right customer is often significantly more profitable than a lower CAC for the wrong one. The right customer pays back faster, spends more over time, and doesn’t drag your retention metrics into the ground.
Optimising purely for CAC reduction is one of the most common ways ecommerce brands sabotage their own growth.
Your goal isn’t cheaper customers. It’s better customers.
Where Most Brands Go Wrong
The mistakes tend to cluster around the same pattern.
CAC targets are set without any real understanding of customer lifetime value. The target becomes a constraint rather than a signal. Everything gets optimised to fit under it.
Ad platforms get told to optimise for cheap conversions rather than valuable customers. The platform finds what you ask for. Cheap is rarely the same as good.
Retention is treated as a separate department’s problem. It’s not factored into acquisition decisions. So the full cost of a poor-fit customer never makes it back to the conversation about acquisition.
Some brands, particularly in crowded categories, have essentially turned their DTC channel into an expensive sampling operation. The first purchase is subsidised. The second purchase never comes. The unit economics only work if they model for a return that isn’t materialising.
And almost no one segments their performance by customer quality. Blended CAC hides all of this. It smooths over the difference between your best customers and your worst, and presents a number that obscures more than it reveals.
The System View
This is where the Manage the Machine framework becomes important.
CAC is not a marketing metric. It is a system metric. It is produced by the interaction of every part of your growth engine. Traffic quality. Conversion rate. AOV. Post-purchase experience. Retention architecture.
When the machine is producing a CAC number that doesn’t work, the answer is rarely to do something different with the ads. The answer is to diagnose which part of the machine is creating the pressure.
If traffic quality is poor, you are attracting the wrong people. Fix the signal.
If conversion is weak, you are failing to build enough purchase confidence with the right people. Fix the product context.
If AOV is low, you are leaving revenue on the table at the point of highest intent. Fix the offer architecture.
If retention is poor, you are losing customers faster than you can afford to acquire them. And no amount of CAC optimisation will fix that. It will just make the treadmill run faster.
These are system problems. They require system thinking.
Acquisition without retention is just expensive sampling.
A Better Set of Questions for Founders
If you are in a business where CAC is a recurring concern, the problem is usually not the question you’re asking. The question itself points you in the wrong direction.
Instead of asking how to lower CAC, try asking these:
| Questions you need to be answering: Who are we actually acquiring? Do we know what kind of customer our current campaigns attract, beyond the conversion metric? What are these customers worth over 12 months? Over 24? Is there a payback model that goes beyond the first order? How quickly do our best customers pay us back? What did we do to attract them? Can we do more of that? Are we attracting the right customer in the first place? Or are we optimising acquisition of the wrong profile more and more efficiently? What does the retention data tell us about acquisition quality? Are there clear patterns between customer source and long-term value? |
None of these questions require a new platform, a new agency, or a new creative strategy. They require a proper look at what your current acquisition activity is actually producing.
The Takeaway
CAC is one of the most watched numbers in ecommerce. It is also one of the most misread.
It is treated as a cause when it is an effect. It is treated as a marketing metric when it is a system metric. It is optimised in isolation when it can only be understood in the context of the customer it represents.
If you are fixing CAC without fixing who you acquire and what they are worth, you are optimising the wrong thing more efficiently. That is not growth. That is precision in the wrong direction.
The brands that scale well are not the ones with the lowest CAC. They are the ones who know their best customers, build systems that attract more of them, and treat retention as the return on their acquisition investment.
Not all revenue is equal. Not all customers are equal. Your growth strategy should reflect that.
Not all customers are equal. Your growth strategy should reflect that.
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