A non-convertible currency is the monetary unit of a country where holders of the currency do not have the right to convert it freely at the going exchange rate into any other currency. A currency is considered as non-convertible if it fulfills one or more of the following three criteria about usability, exchangeability and market value: it cannot be used for all purposes without restrictions; it cannot be exchanged for another currency without limitations; It cannot be exchanged at a given exchange rate.