The best/most inexpensive way is to get a pair of calipers. Accu-measure is the cheapest I could find. You can also get it digital. Its like $25 on amazon.
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Or if you don't wanna buy that, if you have measuring tape, you can use the U.S. Navy circumference method...
your not going to be able to get your bf% without measuring. No calculation online can help without the measurements.
