A project management system is enabled to handle multiple currencies within managed projects. An exchange series includes currency definition parameters such as currency pairing, frequency of rate change, and effective date of exchange rate. Using the exchange series and a strong definition of cost for tasks and resources (i.e. indicating currency type along with value of cost), the project management system allows costs to be entered in local currency. Project level roll-ups are calculated employing time-phased currency conversion based on whether the cost is variable or fixed. For scheduling, speculative conversions are facilitated based on latest actual exchange rate information. Local and project currency costs are provided to a project server for enterprise level roll-ups and multi-project management.