I didn't understand your remark about WeekNo., No of days. With A2 =
A1+1 etc. A2:A12 work fine for me, except they show serial dates. They
are easily switched to date format, e.g.:
Private Sub Calendar1_Click()
Sheets("Sheet1").Range("A1") = Calendar1.Value
Sheets("Sheet1").Range("A2:A12").NumberFormat = "m/d/yyyy"
End Sub

If this doesn't work for WeekNo. or No of days, you can change the
format of A2:A12 in a similar way.

Hth,
Merjet