LTV:CAC Ratio
What is LTV:CAC Ratio?
LTV:CAC = Lifetime value ÷ Customer acquisition costThe LTV:CAC ratio divides the lifetime value of a customer by the cost of acquiring them, and it is the core unit-economics health check: a ratio of 3:1 or higher is the widely used benchmark for a model that can scale profitably.
The formula and a worked example
LTV:CAC = lifetime value ÷ customer acquisition cost, both built on gross profit rather than revenue so the two sides are comparable. Work an example with round, illustrative numbers. A mental health subscription acquires patients at a $200 blended CAC (mid-range of the $120–280 band across AdBoost Health partner accounts). To clear 3:1 it needs at least $600 of lifetime gross profit per patient, which at $120/month and a 70% margin (about $84 of gross profit a month) is roughly seven months of retention. Nothing exotic has to happen; the patient simply has to stay long enough for rebills to stack up to $600.
What the ratio is telling you
| Ratio | Reading | Usual move |
|---|---|---|
| Below 3:1 | Buying revenue at a loss once delivery and overhead are counted | Cut CAC or lift retention and margin before scaling |
| 3:1 to 5:1 | The healthy, scalable band for most health and DTC brands | Scale spend while holding the ratio |
| Above 5:1 | Often under-investing in growth, leaving demand on the table | Spend more aggressively to capture it |
A very high ratio is not automatically a trophy: it frequently means a brand is starving cold prospecting and harvesting cheap, already-warm demand, which caps growth even as the ratio looks pristine.
The ratio hides timing
LTV:CAC answers whether a customer is worth acquiring over their whole life, but it says nothing about how long your cash is locked up getting there. Two brands can both post 3:1 and have completely different cash dynamics, which is why the ratio must be read next to CAC payback: a 24-month lifespan at 3:1 looks fine until you notice payback is nine months and every cohort ties up cash you cannot reinvest. The ratio says the model is viable; payback says how fast you can safely grow it.
Why it matters for health and DTC brands
Because both inputs are forecasts, LTV:CAC is only as honest as the cohort data behind it: a brand two months old claiming an 18-month LTV is extrapolating a lifespan it has not observed, and early cohorts often churn faster than mature ones. Underwrite on an already-observed slice of LTV and treat the long tail as upside. Health and supplement brands should target 3:1 to 5:1 with a contribution margin above roughly 35%, since a healthy ratio on thin margin still loses money once overhead is paid. Because the ratio is retention-driven, the highest-leverage way to improve it is almost always lifting retention, not cutting CAC. Check yours with the LTV:CAC calculator.
Related terms
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