What factors influence the value of a fiat currency?

Question

does it have to do with the number of people using that currency?

Answer 1

Well....All paper currencies of all nations meet the definition of fiat currency since there is no nation left on the gold standard, not even the Swiss Franc.

Interest rates and inflation rates are the two biggest factors. High inflation means too much currency in circulation. High interest rates make it more difficult to borrow, slowing down the economy and at the same time making your currency more attractive to investors.