Another of Excel's functions that can be used to calculate the number of days between a start and end date is DATEDIF.
Not only can this function help you find the number of days between dates, it can also be used to find the number of months or years as well.
One thing however, DATEDIF is undocumented - which means you won't find it listed with other functions in Excel.
To find out the details of using this function, read this tutorial on the DATEDIF Function.
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