Methodology
Cartonindex calculates how much fictional money corresponds to one unit of a real currency. The calculation uses two main inputs:
- A fictional reference with a documented unit count and price.
- A public exchange rate that converts the price into the real currency.
Last reviewed:
General formula
First, convert the reference price:
cost in real currency = source price × real-currency units per source-currency unit
Then calculate the index:
fictional units per real unit = fictional units ÷ cost in real currency
The reverse relationship is:
real units per fictional unit = cost in real currency ÷ fictional units
Fictional reference
The reference can be a physical product or a digital package.
Each comparison identifies:
- The product or package.
- The number of units.
- The region and platform, when relevant.
- The price.
- The price date.
- The limits of the reference.
A Monopoly box contains more than banknotes. A Robux or V-Bucks package can vary by region, tax, platform, or promotion. The result depends on the selected product or package, its price, region, date, and exchange rate.
Exchange rate
Each comparison identifies the data series, institution, quote direction, and observation date.
A central-bank rate can be a reference rather than an available retail price. Fees, spreads, and access restrictions can produce a different result.
Historical data
The historical series preserves the method used for each period. Cartonindex records changes to the product, package, source, or monetary scale.
A redenomination does not appear as a sudden gain or loss. The series uses a common scale or separates the periods.
Limits
The index does not measure:
- The full cost of living.
- Wages.
- A country's wealth.
- Currency quality.
- Future value.
- A guaranteed exchange price.
Cartonindex shows one relationship between documented inputs. Each comparison page provides the traceability needed to reproduce it.