Decimal currency

Decimal currency is a currency for which the ratio between the basic unit of currency and its sub-unit is a power of ten. In practice this usually means that 100 of the sub-unit make up one of the basic unit, but currencies divided into 1000 sub-units also exist, especially in Arab countries. For example, 100 United States cents make one dollar, 100 British pence make one pound, 100 "euro cent" make one euro, 1000 Tunisian millimes make one dinar, 100 Paise make one Rupee, and so forth.

Today, the only currencies which are not decimal are those that have no sub-units at all, plus the Mauritanian ouguiya, 1 ouguiya = 5 khoum, and the Malagasy franc of Madagascar: 1 ariary = 5 Malagasy francs. The latter currency is doubly unusual: note that the "default" unit is actually the smaller unit.

Historically, non-decimal currencies were much more common, such as the British pound sterling before decimalisation in 1971.