Unable to sort dates by oldest to newest

the dates are text and formatting is not really going to help here

all the dates in your sample have // format none have - -

theres is no way of knowing if

09/07/16
is the 7th Sep or the 9th July
because in excel at the moment its just text and NOT a date with a format wrong.

excel uses a number from 1900 for dates
so today for example 25th june 2016 is a number 42546 days from 1900
tomorrow will be 42547

and so excel will look at that number and when you say format as date - it know what to do
at the moment you do NOT have the numbers in excel - so it just treats
25/06/16 and 06/25/16 the same as AB12CD - just text

you cant
as i say you dont know
09/07/16
is the 7th Sep or the 9th July

you can extract the middle 2 characters and if > 12 then you know its DD/MM/YY

but that will not help for dates that are
days 1-12
and
months 1-12

which means day and month can change and still give correct result

01/12/16
is 1st dec
or
12th jan

03/09/14
3rd sep or 9th mar

Maybe convert it this way

popipipo
problem with that is you are assuming US format

ie
04/10/1979 - you converted to 10th April
BUT from the OP post it may also be
4th Oct

04/10/1979 - you converted to 10th April
BUT from the OP post it may also be
4th Oct

mixed format of mm/dd/yyyy and mm-dd-yyyy

The first 2 numbers are always the month


The format of the external source should be the same for all data.
Copy this data as text in excel.

Then use this formula from the raw data that you get from another source

missed that
well spotted
i picked up on

Some remained in mm/dd/yyyy while some changed to dd/mm/yyyy

Some remained in mm/dd/yyyy while some changed to dd/mm/yyyy

That is an action that excel automatically does when you enter the cel with eg 04/10/1979