An exchange rate that eliminates the effects of exchange rate fluctuations and that is used when calculating financial performance numbers. Companies with major foreign operations often use constant currencies when calculating their yearly performance measures. 

|||For example, consider a French company that sells primarily abroad and sets its prices according to U.S. dollars. If sales increase 10% in dollar terms, but the dollar fell 5% against the franc during the year, only a 5% increase in sales will be reported in the accounts, unless a constant currency is applied in the calculation. In other words, the use of constant currencies allows companies to show performance unaffected by currency fluctuations.