The following calculator gives you an estimate of your % bodyfat and lean body mass based on your weight, height, age and simple tape measurements (i.e. anthropometric measurements). Skin-fold measurements alone tend to underestimate body fat percentage in the obese and very lean (particularly with low hydration levels). The following calculator is based on equations which are useful for people in these groups as well as people with loose skin after very large weight loses. It is generally accurate to within a few percent. Anecdotally, it has also proven to be reasonably accurate with drug-free, genetically typical bodybuilders.