Let's look at some of the date formats you might encounter and how to convert them to standard Excel dates.
As figure shows, the formulas in column B convert the data in column A to three results in column C, all of which follow the U.S. date format of mm/dd/yy.
Figure. Date formats converted to valid dates (U.S. format)
Following figure shows the same approach at work, except that the cells in column C were formatted with the European date format of dd/mm/yy.
Figure. Date formats converted to valid dates (European format)
Hopefully, these nifty formulas will take some of the stress out of working with imported dates.