I have 3 sets of customer data - Live new, Lapsed and Renewed each over 1.04m rows. I have an table of formula in excel which will calculate the NPV for customers providing there are less than 1.04m but I'm stuck on how to get this to work when the data exceeds the limit. I've tried calculating across 2 sheets but the formula won't calculate. Is it possible to use access to store the data and get excel to read it from these, without importing the data to excel?