The rial (ISO 4217 code IRR) is the currency of Iran. It is subdivided into 100 dinar but, because of the very low current value of the rial, no fraction of the rial is used in accounting.
When talking money in Iran you may hear the term “Toman”. The toman is an old term but is no longer an official currency. Although the "Toman" is no longer an official unit of Iranian currency, Iranians commonly express amounts of money and prices of goods in "Tomans." For this purpose, one "Toman" equals 10 rials. Despite this usage, amounts of money and prices of goods are virtually always written in rials. For example, the price sign in a store would state the price in rials, e.g., "20000 Rials," even though the salesman, if asked, would say the cost "2000 tomans" or simply 2000.
There is no official symbol for the currency but the Iranian standard ISIRI 820 defined a symbol for use on typewriters (mentioning that it is an invention of the standards committee itself) and the two Iranian standards ISIRI 2900 and ISIRI 3342 define a character code to be used for it.
The rial was first introduced in 1798 as a coin worth 1250 dinar or one eighth of a toman. In 1825, the rial ceased to be issued, with the Qiran of 1000 dinars (one tenth of a toman) being issued as part of a decimal system. The rial replaced the Qiran at par in 1932, although it was divided into one hundred (new) dinars.