I'm sure this has been asked many times before, but I am completely clueless as to how you tell your body fat percentage. I have heard that a lot of the scales that are supposed to tell you are very innacurate, so how do people find out?

It's a calculation based on your weight and height, which can be mildly accurate if you're not a very muscular person or you haven't lost a lot of lean mass from previous dieting.

Scales use a weak electric signal but this method seems to be a novelty and wildly inaccurate.

You can be measured with skin calipers but, again, even this has a level of inaccuracy.

Okay, I found this site that calculated it for me and it said I have 32.8% body fat. That means I have 170lbs of lean body mass and 80lbs of fat. Does this mean that I should weigh 170lbs ideally? The site I used is

Home Body Fat Test

does it seem like a reliable site?

Well the site you listed looks pretty reputable, but like anything these equations are for the "average" person and doesn't take into consideration people who lack a lot of lean mass or have a bodybuilding physique. BMI and body fat percentage, while not completely accurate when using the more simple methods, can act as a benchmark for fat loss especially if the scale isn't moving.

Body fat percentage - Wikipedia, the free encyclopedia
Body Mass Index (BMI) - Wikipedia, the free encyclopedia

As far as what you should weigh, a good estimate can come frame size, height, and gender. You don't want to be totally lean as a certain percentage of body fat helps maintain normal biological activity.

BBLex - Calculator: Bodyfat calculation by US Navy formula

I just used this site and it said my body fat percentage is 53.6%!!!! I dont understand how there can be this big of a difference between 2 calculations!