A calorie calculator is a tool used to specify the amount of daily calories someone needs. The calorie calculator is most often used to prevent weight gain or to simply maintain a current weight, as stated by Mayo Clinic.
A calorie counter uses age, weight, height, gender and activity level to determine the amount of daily calories needed to maintain a healthy weight, per the calculator provided by the Mayo Clinic. The calculator shows a 33-year-old female who stands 6 feet tall and weighs 240 pounds who is somewhat active should have no more than 2,050 calories per day to maintain that current weight. If that same patient was very active instead of somewhat active, the daily calorie intake increases to 2,650.