Methodology

Cartonindex calculates how much fictional money corresponds to one unit of a real currency. The calculation uses two main inputs:

1. A fictional reference with a documented unit count and price.
2. A public exchange rate that converts the price into the real currency.

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 is therefore a reproducible editorial approximation.

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.