Convert.ToDouble (String) converts string to double-precision floating-point number.
Module Example Public Sub Main() Dim values() As String = { "-1,035.7", "1AFF", "1e-35", "190.34001", "1.29e325"} Dim result As Double For Each value As String In values Try result = Convert.ToDouble(value) Console.WriteLine("Converted '{0}' to {1}.", value, result) Catch e As FormatException Console.WriteLine("Unable to convert '{0}' to a Double.", value) Catch e As OverflowException Console.WriteLine("'{0}' is outside the range of a Double.", value) End Try Next End Sub End Module