Body fat percentage is a better indicator than weight for how much fat you’re losing on that diet and/or exercise program you’ve been doing (or contemplating). Unfortunately measuring body fat is either expensive or inaccurate. But if you, like me, happen to find yourself in a pool several times a week, then you can measure %BF for virtually nothing.
Download either the simple one-page whitepaper or the in-depth paper complete with resources and physics equations to learn how. I have also put together a spreadsheet template [OpenOffice.org][Excel 97] for calculating and tracking your %BF.
Or, just follow these instructions for using the spreadsheet.
You can download a nomogram to make calculation of body fat percentage as simple as drawing a line from A to B.
For historical reasons, here are links to my first and second blog posts on the subject.