So I bought one of those scales from costco that is supposed to tell you your body fat %, and the thing just errored on me when I stood on it :-( My BMI is 38. I am pre surgery and hoping to be able to track my fat loss % as an additional way to see progress for the tough times when the scale is not moving.

On Amazon I see some that are hand held for around $25. I also see calipers and they look complicated.

What does everyone use to measure fat loss?

I don't bother. Just have my Personal Trainer take my measurements once a month. Inches lost is a great way to measure progress when the scale isn't cooperating!

I have access to a wellness center that does air displacement measurement to calculate body fat %...I'm not sure I'd trust anything else other than Water displacement or DEXA scanning. You can get an air displacement plethysmography for under $100, then do another in a year to see where you are. Calipers are very dependent on user skill for accuracy, so don't bother buying them. And I've got an Aria scale that supposedly measures my body fat %, but it's remained at EXACTLY the same wrong number for the last 8 months, through 80+ lost pounds...makes me doubt it

I grew up with my father who is all about health and has worked in the medical field for 40+ years. He's always used calipers for his patients. There will most likely not ever be some kind of electronic device that will be as accurate as calipers. Although I do believe many of them can come pretty close. But anyway, calipers are the ones that can't go wrong, unless you read it wrong.