Set calculation to manual to save time in Excel
To do it in Excel, here is the answer:
a) Under "Formulas" tab, click on "Calculation Options". By default "Automatic" would be set. Change it to "Manual".
b) When set to manual mode, Excel does not recalculate automatically as you make updates to Workbook.
Under Formulas, click on "Calculate Now" (or press F9) for Workbook to be re-calculated based on updates.