I got up today and stood on the scale and it showed I had lost 3 lbs since the beginning of July. Woo Hoo. Then just to be sure, I stood on it again and it showed a 5.5 lb loss. Confused, I got off and stood on it again. this time the loss was even greater. What the heck? I changed the battery just last month. I jumped on one more time and it showed the original weight. So I am going with it. No wonder I can't figure out how much weight I have lost or gained.