Calculating protein, how is it done?

Well the protein calculation is based on the "1gram per pound of body weight." That theory is based on your activities. For instance if you live a sedentary lifestyle you'll require slightly less then 1 gram per pound however if you indulge moderately in activities you have to escalate the consumption, if your always in engrossed in physical activites it will be mandatory to have 1.5-2g per pound of body weight. All the best :)