If the scale is giving you different readings after consecutive uses, please check the following; -Ensure that you have calibrated the scale since this could cause a 3-4 pound difference between readings. -Ensure that it is placed on a hard and level surface, the scale will not work on carpet, mats or rubber flooring. -Ensure that the conditions are the same for the user, things to consider are: drinking, eating, items in pockets, using the rest room, phone on hand, etc. *Fun fact: 1 liter of water weighs 2.2 pounds or 1 kg so drinking or urinating will often cause a slight fluctuation.