It’s important to know your energy expenditure whether you’re trying to lose, gain or maintain weight. The amount of calories burned per day and during exercise varies a lot. Knowing your calorie expenditure helps you plan your meals accordingly – it’s key to make sure that you get enough calories to make up for the energy you use. Depending on the fitness/ sports watch you’re using, your daily calorie expenditure estimate will be based on several metrics, such as daily activity, the intensity of your workouts and also your personal information, such as height, weight, age, gender and maximum heart rate.