Any time the scale is moved at all, you will want to recalibrate the sensors. To do this, make sure the scale is on a hard, flat surface. No rug, carpet, or uneven tiles. Also, make sure the 4 rubber feet are intact and free of debris on the bottom. Press on it enough to wake it up, let it settle at 0.0, and let it power off. Without moving it at all, press on it to wake it to 0.0, and then step on to weigh yourself. Let the scale power off and weigh in one more time.