Calorie Ranges. Boys between the ages of 11 and 13 need 1,800 to 2,600 calories per day while boys ages 14 to 18 need between 2,200 to 3,200 calories per day. Girls aged 11 to 13 need 1,800 to 2,200 calories per day while those between the ages of 14 and 18 need 1,800 to 2,400 calories per day, according to the Academy of Nutrition and Dietetics.