2g/kg or 1g/lb
2 grams of protein
(typically whey protein if you are purchasing protein shake as a dietary supplement) per kilogram of body weight
There are about 2.2 kilograms per pound, so divide your weight by 2.2 and multiply by 2 to get a "grams per day" amount for building lean muscle. If you hate math, this calculation equals approximately 1g protein per pound of body weight.