In this example the start date is in cell D17 and the end date is in E17. In another cell use the DATEDIF formula with the ym parameter. Open up the Format Cells dialog box by either.
For example enter 736 into B1.
Type the equation you want to calculate. Percentage of Days spent in Home Town 10 15 100 6666. The simplest and most obvious Excel formula to calculate time difference is this. It is split into two parts one is 10 days in hometown and 5 days in the USA.