The calorie calculator is very useful for weight management as it displays how many calories are needed over the specified period of time. It keeps track of your weight loss and calories required. The less you weigh, the fewer calories you will need to take in for weight loss to continue. This is reflected in the calculator with the corresponding calories intake on a weekly basis. NB: Any (-ve) negative values are shown in red, ie trying to lose 50 pounds in 1 week is not possible. Values in yellow indicates a very low calorie intake. As a rule of thumb you should not eat below 1200 calories for female and 1600 calories for male.