Iran's parliament has passed a bill allowing the government to slash four zeros from the rial, after a sharp fall in the value of the currency as a result of crippling US sanctions. Iran's national currency will be changed from the rial to the toman, which is equal to 10,000 rials, under the bill. "The bill to remove four zeros from the national currency was approved by lawmakers," Iran's Students News Agency reported on Monday. The bill needs to be approved by the clerical body that vets legislation before it takes effect. Iran's state TV said the Central Bank of Iran will have two years to "pave the ground to change the currency to [the] toman". The idea of removing four zeros has been floated since 2008 but gained strength after US President Donald Trump withdrew the United States from Iran's 2015 nuclear deal and reimposed sanctions in 2018. The rial has lost more than 60 per cent of its value since then.<br/> The Iranian currency was trading at about 156,000 rials per dollar on the unofficial market on Monday, according to foreign exchange websites.<br/> Iran's weak currency and high inflation have led to sporadic street protests since late 2017.