The ruble or rouble (; Russian: рубль, IPA: [rublʲ]) is a currency unit. Currently, currencies named ruble in circulation include the Russian ruble (RUB, ₽) in Russia and the Belarusian ruble (BYN, Rbl) in Belarus. These currencies are subdivided into one hundred kopeks. No kopek is currently formally subdivided, although denga (½ kopek) and polushka (½ denga, thus ¼ kopek) were minted until the 19th century. Additionally, the Transnistrian ruble is used in Transnistria, an unrecognized breakaway province of Moldova.
Historically, the grivna, ruble and denga were used in Russia as measurements of weight. In 1704, as a result of monetary reforms by Peter the Great, the imperial ruble of the Russian Empire became the first decimal currency. The silver ruble was used until 1897 and the gold ruble was used until 1917. The Soviet ruble officially replaced the imperial ruble in 1922 and continued to be used until 1993, when it was formally replaced with the Russian ruble in the Russian Federation and by other currencies in other post-Soviet states. In the past, several other countries influenced by the Russian Empire and the Soviet Union had currency units that were also named ruble, including the Latvian ruble, Tajikistani ruble and Transcaucasian ruble (later Armenian ruble, Azerbaijani ruble, Georgian ruble).
