Just do a google search and you can find caliper. Calipers are only good if the person using them has experience, and if the calipers are good (not the rinky dink POS calipers). A good pair of calipers will cost around $200. Underwater weighing is the most accurate, but good luck finding a place that does it (best place to look may be a college with an Exercise Science Department). There's also Bioelectrical Impedance, but there are too many variables that could effect the result.