The rupiah is the monetary unit of Indonesia (currency code IDR).

The name derives from the Indian monetary unit rupee. Indonesia used the Dutch guilder from 1610 to 1817, when the Dutch East Indies guilder was introduced. The rupiah was first introduced by during the World War II Japanese occupation, and after the end of the war the Java Bank briefly issued its own Java rupiah as a replacement. The Netherlands' Nica guilder and various guerrilla-linked currencies were also in use around the archipelago.

Four years after independence, on November 2, 1949 the Indonesian rupiah was introduced as the new national currency. The Riau islands and the Indonesian half of New Guinea (Irian Barat) had their own variants of the rupiah, but these were subsumed into the national rupiah in 1964 and 1971 respectively. Devalued by rampant inflation, on December 13, 1965 the New Rupiah was introduced at a rate of 1000 old rupiah to one new rupiah. The Asian economic crisis of 1998 reduced the rupiah's value by 35% overnight and led to the overthrow of Suharto.

The rupiah is a freely convertible currency, but trades at a penalty due to continued high inflation. As of November 2003, the rupiah's exchange rate is approximately 10,000 to the euro.

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