Tweethydrostatic weighing isn't the most accurate way there is...it is generally off by around 1.7%...the most accurate is the DEXA...which is a low frequency xray...they are pretty new...they measure your complete fat content, not just sub-c, since it is known that about half of your total fat stores are in sub-c, which is what is measured with skin folds, you just take the # for % BF the DEXA gives you and basically cut it in about half...my complete fat stores on wednesday afternoon, where 18.5, which equates to about 10-12% on calipers...