Sub CalculateDays()
'THIS IS GOING TO BE THE DIFFERENCE OF THE START DATE AND THE END DATE
txtDays.Text = CStr(DateTimePicker2.Value.Date.DayOfYear - DateTimePicker1.Value.Date.DayOfYear)
End Sub

This is a function you can call to make your goal happen. I have written several programs that deal with this to include databases and deadlines. It appeared to me that the other posts were not very clear and a bit confusing, so I thought I would step in and help you out.

1. by using the day of the year you are working with a julian calendar and therefore, it allows you to get accurate calculations for the months ahead. I noticed you were using "day" and other objects without success. I hope this helps

Tiffani Hume