WD98: How to Determine the Number of Days Between Two Dates (182432)

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Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. The following Visual Basic for Applications sample macro prompts for a date in the mm/dd/yy format, and returns the number of days between the current date and the specified date.

The DateValue() function converts a specified date, beginning with December 30, 1899, to a serial number.

Syntax: DateValue(DateText$)

Examples

   x = DateValue("12/30/1899")  ' returns 0 or zero
   x = DateValue("12/31/1899")  ' returns 1
   x = DateValue("12/5/1992")   ' returns 33943
				

The Sgn() function is used to determine if the difference between two dates is a negative (date in the past) or positive (date in the future) number.

    Sub DayDiff()
      Dim sDate As String
      Dim intNumDays As Integer
      On Error GoTo errhandler
      ' Prompt for a date.
      sDate = InputBox$("Enter a date in the mm/dd/yyyy format")
      ' Get difference between dates.
      intNumDays = CInt(DateValue(sDate) - Now())
      ' Determine if difference is past or future.
      If Sgn(intNumDays) = 1 Then
         MsgBox "Days between " + sDate + " and today :" + CStr(intNumDays)
      Else
         MsgBox "The date " + sDate + " was" + CStr(Abs(intNumDays)) _
         + " day(s) ago."
      End If
   errhandler:
      If Err > 0 Then MsgBox "Please enter a valid date."
   End Sub
				

For additional information, please see the following article in the Microsoft Knowledge Base: