Calculating the ketogenic diet requires a combination of a full nutritional assessment and an understanding of the child’s medical condition, mixed with experience and intuition. In each case, a child’s individual needs must be taken into account. Calculating the caloric requirements of an individual child requires consideration of both the child’s current and desirable weight as well as the patient’s activity level. The caloric needs for patients on the ketogenic diet is calculated using the Dietary Reference Intakes or whichever calculation the dietitian feels will meet the patient’s needs. This chapter provides a brief description on estimating caloric needs; general rules for initial ketogenic diet calculation; and calculating meal plans. Calculating the meal plan, in contrast to the diet prescription, is a fairly straight-forward procedure. There are currently two different ways of calculating the meal plans: by hand or by computer.