This calculator estimates your specific daily calories or energy and macronutrient (protein, carbohydrate and fat) recommendations based on the data you provide when answering the following questions. 1. Physical attributes. Your height, weight, age and gender are used to calculate your basal metabolic rate, which is the minimum amount of calories you need every for your body to function. This data is inputted into the Harris-Benedict formula, one of the most used predictive equations for energy expenditure in clinical practice Globally. The calorie estimation calculated at this step is the bare minimum amount of energy you need to function daily. 2. Daily and planned physical activity level. Once your basal metabolic rate is estimated using the Harris-Benedict formula, the next step is to adjust this number based on how active you are daily, which includes any planned exercise sessions. This calculates an estimation of how many calories you need daily to sustain your activities and maintain a constant body weight. 3. Physical Goals. This data contributes to personalizing your daily energy, protein, carbohydrate and fat recommendations based on your overall body composition. For example, if you choose a goal of weight loss, your daily calorie recommendations will be reduced by 500 kcal. This is based on the simple equation that to lose 1 lb. weekly you require a daily calorie deficit of approximately 500 calories. Similarly, if you goal is to build muscle or gain muscle bulk, your daily calorie recommendations will be increased by 250-500 calories respectively, as muscle growth is an energy expensive process and requires an increase in daily calories.