Imports System
Public Class Program
Public Shared Function PercentageStringToDouble(ByVal value As String) As Double
Return Double.Parse(value.Replace("%", "")) / 100
End Function
Public Shared Sub Main()
Dim str As String = "12.57%"
Console.WriteLine(PercentageStringToDouble(str))
End Sub
End Class
' run:
'
' 0.1257
'