When speaking about calories, It depends on the individual themselves. If they are active and work around a lot, They need more calories to sustain nutrients in their bodies. If they are someone who lounges around and does not work much, they need lesser calories because the more calories someone has, the more they will need to burn. Doctors say on average, an 8-13 year old is expected to intake around 1,800-2,200 Calories a day.