Decimalisation
Conversion of currency or measures to powers of 10.
Decimalisation is the conversion of a currency or system of weights and measures to units related by powers of 10. Most countries have decimalised their currencies, converting from non-decimal sub-units to a decimal system with one basic unit and sub-units valued by a power of 10, most commonly 100. While Russia introduced a decimal ruble in 1704 under Tsar Peter the Great, making the silver ruble equal to 100 copper kopecks, earlier decimal systems existed—such as the Chinese cash coin system and the Russian ruble's own decimal division in the 16th century.
- First country
- Not applicable (earlier decimal systems existed)
- Field
- Currency and measurement reform
- Known for
- Conversion to decimal currency and metrication
- Current non-decimal currencies
- Mauritania (1 ouguiya = 5 khoums), Madagascar (1 ariary = 5 iraimbilanja)
- Undecimalised common units
- Time
Lore & Background
Decimalisation has been applied to currencies worldwide, with Russia adopting a decimal ruble in 1704, though earlier decimal systems existed, such as the Chinese cash coin system and Russia's own 16th-century decimal division. The French Revolution introduced the franc in 1795 and attempted decimal time, which Napoleon abolished after eleven years. The United Kingdom and Ireland decimalised sterling and the Irish pound in 1971. For weights and measures, decimalisation is called metrication, replacing traditional units with the metric system, adopted by almost all countries except the United States, and to a lesser extent the United Kingdom and Canada.
Reader's Guide
Decimalisation simplified trade and accounting by replacing complex non-decimal systems with units based on powers of 10. Its adoption facilitated international commerce, as seen in the United States' Coinage Act of 1792 and Canada's decimalisation in the 1850s to align with its largest trading partner. The process often involved renaming currencies, such as Sweden's riksdaler becoming the krona in 1873. While most currencies are now decimal, Mauritania and Madagascar retain de jure non-decimal systems, though their sub-units are no longer used. Metrication, the decimalisation of physical measurements, has been nearly universal, with electrical units decimalised worldwide. Time remains the notable exception, as decimal time failed after the French Revolution. Decimalisation's legacy is a global standard that reduced errors and eased calculations, though some countries transitioned gradually, as in Mexico where pre-decimal coins were issued until 1897.
Did You Know?
- Though Russia introduced a decimal ruble in 1704, earlier decimal systems existed, such as the Chinese cash coin system and the Russian ruble's own decimal division in the 16th century.
- Only two countries have de jure non-decimal currencies: Mauritania and Madagascar.
- An attempt to decimalise time during the French Revolution was abolished by Napoleon eleven years later.
- The United Kingdom and Ireland decimalised sterling and the Irish pound in 1971.
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