Credits (science fiction)

A fictional currency is some form of currency defined, or alluded to, in works of fiction. The names of units of such currency are sometimes based on extant or historic currencies (e.g. "Altairian dollars" or "Earth yen") while other names, such as "Kalganids" in Asimov's Foundation series, may be wholly invented. A particularly common type, especially in science fiction, is electronically managed "credits". In some works of fiction, exchange media other than money are used. These are not currency as such, but rather nonstandard media of exchange used to avoid the difficulties of ensuring "double coincidence of wants" in a barter system.

Authors have to take care when naming fictional currencies because of the associations between currency names and countries; recognizable names for currencies of the future (e.g. dollar or yen) may be used to imply how history has progressed, but would appear out of place in an entirely alien civilization. Historical fiction may need research. Writers need not explain the exact value of their fictional currencies or provide an exchange rate to modern money; they may rely on the intuitive grasp of their readers, for instance that one currency unit is probably of little value, but that millions of units will be worth a lot.

Currencies in science fiction face particular problems due to futuristic technology allowing matter replication and hence forgery. Authors have proposed currencies that are incapable of replication such as the non-replicable "latinum" used by the Ferengi in the Star Trek universe, or the currency in Pandora's Millions by George O. Smith, which is booby-trapped to explode if scanned by a replicating machine. Money in fantasy fiction faces analogous challenges from the use of magic; in the Harry Potter series by J. K. Rowling, magically-created currency is time-limited, while in Ursula K. Le Guin's fictional realm of Earthsea, the world's equilibrium is unbalanced when something is created from nothing.

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