double.Parse(double.MinValue.ToString()); //or double.Parse("-1.79769313486232E+308"); //and double.Parse(double.MaxValue.ToString()); //or double.Parse("1.79769313486232E+308"); These codes will throw a System.OverflowException which says "the value is too big or too small as double", while float with float.MaxValue and float.MinValue does not.