Hi Laurent, How are you doing? I need to use PowerPivot to calculate IRR for a dynamic number of investments. My table is structured like this: Project Name, Event Date, Cash Flow. In Excel, I would XIRR as the cashflows are not regular. Do you have any ideas on how this can be done? The difficulty here is that IRR is an iterative calculation and there is no way to reproduce it without using Excel function.Using CALCULATE and time intelligence functions might help making your model more maintainable, provided you have a date table, since you would not have to referrence p or any other column in your table (except Y and C).