A dirty float, also known as a managed float system, is an exchange rate system where the value of a currency is determined by supply and demand factors in the foreign exchange market, but where the government or central bank occasionally intervenes to stabilize or manage the currency.
A fixed exchange rate is an exchange rate system where the value of a currency is pegged by the government to that of another currency, a basket of currencies, or a measure of value, such as gold. The government maintains this rate through economic policies and interventions in the foreign exchange market.
A floating exchange rate is a type of exchange rate regime wherein a currency's value is allowed to fluctuate due to market forces without direct governmental control. However, governments and central banks may intervene to stabilize the currency if necessary.
