Understand how those things work, it takes the shortest route, eg up the 1 leg down the other....
Only way to get a BF done is by a personal trainer or somebody that knows what they doing, 'pinch tests'.
You can messure your own but you can also get wrong results if you don't know EXACTLY where to measure there is allot of calculators online to measure your BF, eg: punch in the different readings and it will give your result but you need to really know how to do it yourself....
become friends with a trainer at the gym and pop the question (haha pop the question) and let them guide you to do it CORRECTLY. it takes awhile to get it down to an art....
"Whether You Think You Can or Can't, You're Right"--Henry Ford