According to the country’s central bank, the new currency will be valued at about 10 to the US dollar.
The leone has been falling since austerity measures were introduced in 2017.
With mining companies and the government in a long-running battle, the Covid-19 pandemic has made things worse.
The central bank governor, Prof Kelfala Kallon, said the move would make it easier for people who had to go around carrying “a whole amount cash to just do something very simple.”
He told the BBC’s Focus on Africa radio programme that people had been putting themselves at risk with thieves “lurking around [banks] to see who is coming out with a big sack and then they follow them”.
The governor said the re-denomination would also give a “psychological boost” for Sierra Leoneans.
No date has been given for when exactly the new leone, as it’ll be called, will be introduced