On a Mac select Calculation. To determine how many weeks elapsed between two dates we can use a simple formula to find the number of days between the dates then divide by 7. After installing Kutools for Excel please do as follows.
The formula will look like this.
On a Mac select Calculation. In the Date Time Wizard dialog window switch to the Difference tab and do the following. It is written in Excel as TODAY. For example if you have a number of tasks for which you want to find due dates enter a heading such as Start Date in cell A1.