I've always had mine done with calipers. I've used one of the scales, but I didn't believe the results that it gave me. If you are a member of a fitness center or a gym, just ask the owner or trainer there and see if they can do it. If not you can have a physical done and ask them to that as part of it.
The hydro based body fat count is the most accurate nonetheless.. I have tried the calipers many times and then came this machine that u enter in your stats and then place both hands on sensors and then you get a reading. One time I read at 12.6 which is great but couple days after I had a 14.7 which is in the borderline of great and a good reading .The battery operated machine is more accurate than the calipers but the water testing is the best and I dont think its cheap either lol.