Changing a Selection of Cells to Calculate Manually I am having an issue where I have an array formula that takes very long to calculate and it is slowing down my whole workbook when it is on auto-calculate.  I need auto-updating formulas in the workbook but I was wondering if I could change the cells that have the very time intensive formula to only calculate when I prompt it to so that the rest of the workbook could work as it is meant to and in a timely manner.  Is this possible and how would I do it if it is possible?  I have messed around with calculation options in the formulas tab and haven't found a way to achieve this.