Decimalisation or decimalization (see spelling differences) is the conversion of a system of currency or of weights and measures to units related by powers of 10.
Russia was the first country to convert to a decimal currency when it decimalised under Tsar Peter the Great in 1704, resulting in the silver ruble being equal to 100 copper kopeks.
[2][3][page needed] For weights and measures, this is also called metrication, replacing traditional units that are related in other ways, such as those formed by successive doubling or halving, or by more arbitrary conversion factors.
Common units of time remain undecimalised; although an attempt to do so was made during the French Revolution, this proved to be unsuccessful and was quickly abandoned.
After the October Revolution, the Soviet Union transitioned to a purely decimal model by eliminating the non-decimal subdivisions of the kopek.
The Dutch guilder decimalised in 1817, becoming equal to 100 centen (instead of 20 stuivers = 160 duiten = 320 penningen), with the last pre-decimal coins withdrawn from circulation in 1848.
The United Kingdom (including its overseas territories) and Ireland decimalised sterling and the Irish pound, respectively, in 1971.
Decimalisation was introduced into the Thirteen Colonies by the American Revolution, and then enshrined in US law by the Coinage Act of 1792.
[5] In June 1851, the Canadian legislature passed a law requiring provincial accounts to be kept decimalised as dollars and cents.
A Decimal Coinage Commission had been set up in 1956 to consider a move away from the denominations of pounds, shillings and pence, submitting its recommendation on 8 August 1958.
A television campaign containing a memorable jingle, sung to the tune of "Click Go the Shears", was used to help the public to understand the changes.
The following table shows the conversion of common denominations of coins issued in modern India and Pakistan.
Mauritania and Madagascar theoretically retain currencies with units whose values are in the ratio five to one: the Mauritanian ouguiya (MRU) is equivalent to five khoums, and the Malagasy ariary (MGA) to five iraimbilanja.
[13] Similarly, in the United Kingdom, the prices of government securities continued to be quoted in multiples of 1⁄32 of a pound (7+1⁄2 d or 3+1⁄8 p) long after the currency was decimalised.
The idea of measurement and currency systems where units are related by factors of ten was suggested by Simon Stevin who in 1585 first advocated the use of decimal numbers for everyday purposes.
One aspect of measurement decimalisation was the introduction of metric prefixes to derive bigger and smaller sizes from base unit names.
[16][17] The gradian or grade is an angular unit defined as one hundredth of the right angle (approximately 0.0157 rad), further divided into one hundred centigrades.