This body mass calculator is so easy to use and can be used by both people who know the metric system or the imperial system. You simply put numbers into the boxes it asked you for and then it calculates it easily. Use this calculator for yourself or others, use it whenever you wish. But also let it be known that although it can give you your BMI number, always talk to a doctor about your overall health because there can be other factors in determining ones health and fat levels other than a calculator.