Lifetime Value (LTV)
Lifetime value, or LTV, is the present value of the contribution margin a customer produces over the entire time they stay with a business, not only their first purchase. By the standard convention it is measured before acquisition cost: CAC is compared against LTV separately, which is what allows a ratio like 3:1 LTV:CAC to mean anything. It sets the ceiling on what the business can afford to spend acquiring a customer. Most companies do not track it well: in a CMO Council and Deloitte Digital survey of 150 global marketing leaders, only 17% of senior marketers said their firm tracks lifetime value well ("Humanizing + Analyzing Relationships To Drive Revenue, Retention And Returns," 2021).
How it actually works
The calculation is a present value: the expected contribution margin the customer produces in each future period, multiplied by the probability the customer is still active in that period, summed across periods and discounted at the company's cost of capital. LTV is a stream of future margin, and a dollar of margin three years out is worth less than a dollar today, so an undiscounted LTV overstates the asset and any IRR or payback conclusion built on it. Acquisition cost stays outside the formula; the comparison of CAC against LTV is a separate step. The determining inputs are contribution margin per period, purchase frequency, retention, and the discount rate. A thin-margin one-time customer and a high-margin repeat customer can look identical on the first sale and be opposites over a year.
Two estimation errors dominate in practice. First, the common shortcut of average margin per period multiplied by average tenure overstates LTV whenever churn is front-loaded, because it spreads the survivors' long tenures across customers who left in the first months; the correct computation follows the cohort's actual retention curve, period by period. Second, cohorts that have not lived out their full life understate LTV because their later periods have not happened yet, while extrapolating their early retention forward overstates it, so immature cohorts are reported as partial and projections come from cohorts old enough to show the full curve.
LTV describes a relationship over time, so no single transaction or ROAS figure contains it. Read against acquisition cost and payback period, it identifies which customers are worth acquiring at what price.
Without it, teams optimize for the cheapest first sale. That acquires low-value customers who do not return, blended CAC rises as the base churns, and the campaigns acquiring customers who do return report weaker first-sale numbers and lose budget.
In practice
At Old School Labs, the most profitable cohort in the business came in at a 0.6 ROAS. Margin on the product was high and the customers returned, so lifetime value exceeded what the first-sale number implied, and the cohort outpaced the second most profitable one by five times. The time dimension also matters in the other direction: at one company with a 40% cancellation rate, the payback period on current marketing spend produced a negative internal rate of return. No ROAS report contained either fact, because both depend on what customers do after the first sale.
Where we come in
We build the model that ties acquisition cost to lifetime value and payback period, showing which customers and channels compound and which lose money after the first sale. It is the same measurement approach behind our work with Potbelly, Digital Realty, and Equinix.
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Related terms
- CLV (customer lifetime value)
- Another name for LTV, the present value of the contribution margin a customer produces over their full relationship with a business, measured before acquisition cost.
- Cost of capital
- The rate a company pays for the money it invests, and the discount rate applied to LTV's future margin. Discounting at it is what makes LTV comparable to the acquisition cost paid today.
- Churn rate
- The percentage of customers who stop buying or cancel in a period. It works directly against lifetime value: the faster customers leave, the less each is worth.
- Cohort analysis
- Grouping customers by when they joined and tracking each group over time. It shows whether newer customers are worth more or less than older ones, a difference an average LTV hides.
- Payback period
- How long it takes to recoup acquisition cost from a customer's contribution. Payback period is measured in time, which is the dimension LTV adds and single-transaction metrics lack.