Get Integer value from String using VBA

Since you are using SAP, I think it is safe to assume that the document number will always have a length of 10 characters. So, you can extract it using the Right function, then just convert it using Val. Something like this:

yourInteger = Val(Right(yourSAPString, 10))

Note: in .net, you could use Convert.ToInt32 instead of Val

You could use the split function:

Dim strSplit As Variant
Dim yourNumericOut As Variant

    strSplit = Split("Standard PO created under the number 4500290636")

    If IsNumeric(UBound(strSplit)) Then yourNumericOut = --strSplit(UBound(strSplit))

Then test for numeric, will allow for many lengths and could change the position of the number in the returned values.

I would recommend using a custom function.

Here is the function:

Public Function ExtractNumber(fromString As String) As Double
    Dim RegEx As Object
    Set RegEx = CreateObject("VBScript.RegExp")
    With RegEx
        .Pattern = "(\d{1,3},?)+(\.\d{2})?"
        .Global = True
        If .Test(fromString) Then
            ExtractNumber = CDbl(.Execute(fromString)(0))
        End If
    End With
End Function

Here is the usage example:

Sub Example()
    Debug.Print ExtractNumber("Standard PO created under the number 4500290636")
End Sub

This code was taken from a similar, more recent answer that has better solutions. See here: Excel VBA - Extract numeric value in string