In Excel, the date format depends on the locale setting of the computer, e.g. the formula =TEXT(TODAY(),"YYYY-MM-DD") only works correctly on computers set to English locales, and =TEXT(HEUTE(),"JJJJ-MM-TT") works on German computers. This VBA macro adds =PORTABLE_TODAY(), which fixes this problem and works on any computer.

PortableDate.vba

Public Function PORTABLE_TODAY()
    Dim monthString As String
    Dim dayString As String
    Dim month As Integer
    Dim day As Integer
    
    month = Int(DatePart("m", Now()))
    day = Int(DatePart("d", Now()))
    
    If month < 10 Then
        monthString = "0" & month
    Else
        monthString = month
    End If
    
    If day < 10 Then
        dayString = "0" & day
    Else
        dayString = day
    End If
    
    PORTABLE_TODAY = DatePart("yyyy", Now()) & "-" & monthString & "-" & dayString
End Function