Try:
Code:
Private Sub CommandButton1_Click()
Dim i As Long
With ActiveDocument
For i = 2 To 19
.ExportAsFixedFormat OutputFileName:=Split(.FullName, ".doc")(0) & "_" & Format(i - 1, "000") & ".pdf", _
ExportFormat:=wdExportFormatPDF, Range:=wdExportFromTo, From:=i, To:=i
If i = .ComputeStatistics(wdStatisticPages) Then Exit For
Next
End With
End Sub