The Ecomm Analyst

There is no universal good CAC for e-commerce. A good CAC is any acquisition cost that sits comfortably below the contribution profit a new customer produces, either on the first order or across a payback window you can actually finance. For most brands in the $1M to $20M range, that tends to land somewhere between 20 and 40 percent of first order revenue. But the benchmark that matters is your own margin structure, not a number pulled from a category report.

Why do published CAC benchmarks mislead?

Every published benchmark blends brands with wildly different gross margins, repeat rates, and price points. A skincare brand running 80 percent gross margin with a 45 percent repeat rate can survive a CAC that would sink a furniture brand at 35 percent margin selling one item every four years. When an operator anchors on the average DTC CAC being some specific dollar figure, they are usually comparing themselves against a distribution they are not part of.

The second problem is quieter. Most benchmark data is built from platform reported CAC, meaning ad spend divided by platform attributed conversions. That denominator is inflated on every channel simultaneously, so the resulting benchmark runs systematically low. Comparing your honest number against everyone else’s optimistic number is a losing game.

What math sets your CAC ceiling?

Start with contribution profit per new order. Take average order value, then subtract COGS, payment processing, shipping and fulfillment, discounts, and expected returns. What is left is the money available to acquire that order and still come out ahead.

If AOV is $80 and contribution profit is $34, then $34 is your break even CAC on a first order basis. Below that, you are profitable on order one. Above it, you are placing a bet on repeat purchase. Most brands I work with are making that bet, sometimes without realizing it. The question is not whether the bet is reasonable. It is whether you have the cash to carry it while it pays off.

How does the payback window change the answer?

A CAC of $60 against $34 of first order contribution is fine if the second purchase arrives in six weeks and you have the working capital to float the gap. The same CAC is dangerous if the second purchase arrives in eleven months and you are financing inventory on a credit line.

So the real question is not what CAC is good. It is how many months of contribution profit it takes to recover acquisition cost, and whether your balance sheet tolerates that number. Brands with fast repeat cycles can run CAC well above first order contribution. Brands selling considered, infrequent purchases usually cannot.

Should you use blended CAC or new customer CAC?

Both, for different jobs. Blended CAC, meaning total marketing spend divided by total new customers, is the number that reconciles against your bank account. It is the honest one. New customer CAC by channel is directionally useful for allocation decisions, but it depends entirely on attribution, which means it depends on assumptions you should be able to state out loud.

The mistake I see most often is dividing total ad spend by total orders rather than new customers. That produces a flattering number that improves automatically as your repeat base grows, even while acquisition efficiency is getting worse. If your CAC has been quietly improving for three quarters while spend climbs, check the denominator first.

What is a reasonable starting range?

If you need a rough orientation before doing the margin work, here is what I see across sub $20M stores. Brands at 70 percent or better gross margin with a genuine repeat cycle often run CAC at 40 to 60 percent of AOV and stay healthy. Brands at 40 to 55 percent margin usually need CAC under 25 percent of AOV to avoid financing problems. One item, low repeat categories generally need to be profitable on the first order or the model does not work.

Treat those as orientation, not targets. Run your own contribution math before you set a ceiling. The same logic applies on the return side of the equation, which I walked through in what counts as a good ROAS.

What I check before trusting a CAC number

Three things. First, whether the denominator is new customers or all orders. Second, whether the numerator includes agency fees, creative production, affiliate payouts, and app subscriptions, or only media spend. Third, whether the figure is blended or attributed, because a channel level CAC that sums to less than your blended CAC means the platforms are claiming customers they did not bring.

Fix those three and you will have a number worth arguing about. Until then, the benchmark question is premature.