Harley, from what I've heard and read BF% wise they can be off by as much as 9%. If you drink water your reading will change by as much as 5% - so imagine if you're dehydrated or if your muscle are particularly swollen that day?

I am no expert when it comes to these scales, but every few weeks this question gets posted over at lean & strong and the advice is always stick with measurements, a second set of objective eyes and the 'pant-o-meter' for progress information.

Bottom line is don't let a second scale reading get you down. Just as a scale weight reading can be inacurate so can a BF% reading.

Nat