How do I find out my body fat %

I've used the Army Body Fat Calculator you can find on google. I'm not sure how accurate it is but it's something if you can't get it professionally measured.

The two methods of measuring body fat (BF) that are considered the most reliable are: the DXA scan (bone density xray) and Hydrostatic testing (underwater weighing). Cost and availability varies by location. They are both available in northern CA where I live. My BF has been measured by both methods multiple times. DXA results are generally higher than Hydrostatic. Cost is between $39-45 per scan/test.

Tape measurement methods (like the Army calculator) are a variant of the BMI calculator based on certain body size assumptions and measurement error. Calipers can be reasonably accurate if the measurements are performed by an experienced user but there are few experienced users; you cannot make all the necessary measurements by yourself. Bio-electrical devices generally considered to be unreliable are susceptible to inaccuracies related to gender and water consumption/retention.

Here's a link to an article which discusses the pro and cons of each of these (and some other methods): http://www.bodybuilding.com/fun/body_fat_tests.htm

FYI, my BF% as measured by DXA in Oct 2016 was 16% and in Nov 2016 it was 16.4%. My BF% as measured by Hydrostatic testing in Sep 2016 and in Dec 2016 was 16.9% and 12% , respectively. The Army calculator just gave me a BF% of 16%. And my Omron handheld bio-electrical device (after having dinner and drinking a lot of water) just measured my BF at 15.1% but it gave me a measurement of over 18% just a few days ago.

Based on the DXA and Hydrostatic measurements, my preferred measurement methods, I'm reasonably confident that my BF is somewhere between 12-16% I have visible abs and a lot of muscular definition. So, I would like to think that I am closer to 12 than 16 but there's no way to really know w/absolute certainty. It's nice that the Army calculator and the latest bioelectrical measurement are w/in this range but I would not rely on them personally.

All you can do is pick your poison (the method of measurement you like the best), hope it is reliable and consistent and stick w/it over time to measure the trend.

Good luck!