Net Energy (kcal/kJ) = Energy Consumed - Energy Expended through Exercise
In other words, net calories are the difference between the energy you take in (food/drink) and the energy you burn through exercise (activity). Net Calories = Calories Eaten (Food/Drink) - Calories Burned (Exercise).
Some people like to see the impact of exercise on their energy target. They aim to keep net calories even with their Calorie Budget each day.