LTV to CAC Ratio for DTC Brands

LTV:CAC is the most quoted number in direct-to-consumer and one of the least reliably computed. Two independent errors push it in the same direction, and a brand can be running at a genuine 1.4x while reporting 5.5x without anyone having done anything dishonest.

What the ratio is for

It answers one question: over the whole relationship, is a customer worth more than they cost to acquire?

That is a different question from whether the first order was profitable. A business can lose money on order one and still be sound, provided customers come back reliably enough and you can fund the gap in the meantime. The ratio is how that argument gets made — and it is also how the argument gets made badly, because a high enough number appears to justify any acquisition cost.

Both halves have to be honest for the comparison to mean anything, and in practice neither usually is.

The numerator problem

Lifetime value should be margin, not revenue.

Revenue LTV counts the full order value across a customer’s orders. But that money still owes the cost of the goods, the shipping label, the payment fee and the packaging. None of it is available to pay for acquisition, because it has already been spent on serving the order.

The inflation is roughly the inverse of your contribution margin rate. At a 35% margin, revenue LTV is about 2.9 times margin LTV. So a brand quoting 5.5x on revenue is describing something closer to 1.9x in money it could actually spend — before the second error is corrected.

This is the more common of the two mistakes because revenue LTV is the easier figure to obtain. Shopify knows what customers paid. It does not know what the orders cost you.

The denominator problem

Acquisition cost should count new customers only.

The usual computation divides advertising spend by orders, or by customers, in a period. Both include people who were already customers. If a third of your orders are repeats, the resulting CAC is about a third too low — and repeat buyers are exactly the people advertising least needed to reach.

There is a second, smaller understatement: platform-reported cost per purchase excludes agency fees, creative production, tax on ad spend, and any acquisition-specific discount. A first-order code at 15% off is an acquisition cost that lives in the discount line rather than the ad account.

Correct both and CAC frequently rises by a third or more. In the worked example above it moves from $34 to $46.

Why the two errors compound

Each error alone would be recoverable. Together they multiply.

An inflated numerator and a deflated denominator move the ratio in the same direction, and the resulting figure can be three to four times the real one. That is the difference between “we have room to spend far more” and “we are one CAC increase from unit economics that do not work” — and the two conclusions lead to opposite decisions about budget.

The failure mode is specific and slow. A brand computes 5x, concludes acquisition is cheap relative to customer value, and scales spend. CAC rises with scale, as it always does. The reported ratio falls to 4x, then 3.5x, and still looks healthy against the 3x convention. Meanwhile the real ratio passed 1.0x somewhere during the second increase, and every order added since has consumed cash. Revenue grew the entire time.

What to do with the number once it is right

Read it alongside payback period rather than instead of it.

The ratio tells you whether the customer is worth acquiring. Payback tells you how long your money is committed before you find out. A 3x ratio with a two-month payback is a business that can self-fund growth; the same 3x with a fourteen-month payback needs working capital it may not have, and is far more exposed if retention comes in below forecast.

Then read it by cohort rather than in aggregate. A blended 3x is frequently one acquisition channel at 6x paying for another at 1x, and the aggregate hides the fact that reallocating budget between them would improve the business more than any campaign optimisation.

Where the pieces come from

Computing this properly needs three things that live in different places, which is the practical reason it is so often approximated.

Repeat behaviour by cohort — how many orders a customer acquired in a given month has placed since, rather than a store-wide average that older cohorts dominate.

Contribution margin per order — which needs the carrier invoice rather than the shipping you charged, the real gateway deduction rather than a blended percentage, and refunds attributed back to the originating order.

New-customer CAC — total acquisition spend, including the parts that never appear in an ad account, over genuinely first-time buyers.

None is individually difficult. Joining all three, monthly, without it becoming somebody’s second job is the part that usually does not happen.

A note on the 3x convention

The familiar 3:1 target comes from SaaS, where gross margins commonly run at 75–85% and marginal delivery cost is close to zero. Physical products do not work that way: a 35% contribution margin is respectable in DTC and would be alarming in software.

Transplanting the benchmark without adjusting for that is how a target gets treated as a floor. Better to derive your own: work out what your fixed costs are per order at current volume, and the ratio you need is whatever leaves that covered with something left. That number is specific to your business and it is the one worth hitting.