Premeditation is planning, plotting or deliberating before doing something. For example, murder by poisoning automatically includes an element of premeditation. Premeditation is an element in first degree murder and shows the element of intent necessary to convict of the crime.
The amount of time necessary between the planning and the act to prove premeditation is judged on a case by case basis. Murder in the first degree consists of an intentional, deliberate and premeditated killing, which means that the killing is done after a period of time for prior consideration. The duration of that period cannot be arbitrarily fixed. The time in which to form a deliberate and premeditated design varies as the minds and temperaments of people differ, and according to the circumstances in which they may be placed.