Hi Jaya ,
The issue is that the format is something that will come into play only for valid dates ; for dates which Excel cannot recognize as valid dates , Excel will treat them as text , and for text strings , date formats will do nothing.
So , the first step is to ensure that all your dates are valid dates.
It is of no use if some dates are recognized as valid dates.
If your system date format ( which is solely to do with your operating system , and nothing to do with Excel ) is mm/dd/yyyy , then a date such as :
1/3/2016
will be interpreted as January 3 , 2016.
If your system date format is dd/mm/yyyy , then a date such as :
1/3/2016
will be interpreted as March 1 , 2016.
When you are processing thousands of dates spanning several months , such mis-interpretation of dates can be missed.
Hence , the starting point is to ensure that the dates in your worksheet are interpreted correctly. For this , you need to ensure that your data is in the same format as your system date format.
Thus , if your dates are :
24/06/2016 , with or without a time component
then , if your system date format is dd/mm/yyyy , there is no problem , since Excel will interpret all your dates correctly.
However , if your system date format is mm/dd/yyyy , there will be two problems :
1. Dates where the month component is less than or equal to 12 will be treated as valid dates , but interpreted wrongly. 11/9/2016 will be interpreted as November 9 , whereas it should be interpreted as September 11.
2. Dates where the month component is greater than 12 will be treated as invalid dates.
Narayan