Desde is an utility for windows that shows you the day of the week from almost any date (it will show the day of the week in the language of your system, on my system, it happens to be Dutch).
You can also calculate the difference in days between two dates:
This example shows the difference between 4/15/2001 and 12/10/1954 (My birthdate hehehe).
P.S.: Don't worry, the day of the
week reads out in Dutch, but on English systems, it will show up