A marketing team in Argentina looks at the dashboard and LTV went up again. Nobody changed anything: same product, same funnel, same customer base. What went up was the price of everything else, and that increase slipped, unannounced, into the metric used to decide how much to spend acquiring a new customer.
Nominal LTV does not tell growth from drift
The standard LTV calculation sums each customer historical spend in the currency the business bills in, and quietly assumes a unit of that currency six months ago is worth the same as one today. In a high-inflation country that assumption breaks every month: a cohort that bought the same in real units as the previous one shows up with a higher LTV purely because prices rose between one purchase and the other.
The problem is not exclusive to LTV: it hits average order value, CAC, and any revenue series in local currency. But LTV carries the most weight in deciding how much to invest in acquisition, so that is where the error costs the most. If the number that sets your CAC ceiling is inflated, you overpay for every new customer without noticing.
How to separate real growth from the price effect
The logic is simple even if the calculation takes work: convert each historical transaction to the purchasing power of a reference month, using a public price index, before adding it to the customer LTV. That way, a March purchase and an August one end up in the same real unit and compare cleanly, with no inflation in the middle. There are two ways to do it:
- Deflate by a price index. Multiply each transaction by the ratio between the reference month index and the purchase month index. This is the more precise method for a business operating only in the local market.
- Measure in a stable currency. Convert each transaction at the day exchange rate. Simpler, but the exchange rate and inflation do not always move at the same pace, so it can under or overstate real value depending on the moment.
Either is better than adjusting nothing. What does not work is mixing the two: nominal in the budget meeting, adjusted only for internal analysis.
What changes when the team looks at the real series
When revenue and LTV are always reported in two versions, budget conversations change. It is the standard we apply in data marketing for Argentina: every cohort carries its real series, because nominal growth that is actually a real decline ends up funding the wrong decision. The lifecycle-stage framework in customer retention by stage starts from the same premise: without a reliable metric, any segmentation built on top of it inherits the same error.
If your business bills in a high-inflation currency and you have never compared nominal LTV against the adjusted version, the gap between the two numbers is probably bigger than you expect.