Abstract: A method of determining information relating to the mass of a semiconductor wafer is disclosed. The method comprises loading the semiconductor wafer on to a measurement area of a weighing device having weight compensation means arranged to compensate for a predetermined weight loaded on to the measurement area; generating measurement output indicative of a difference between the weight of the semiconductor wafer and the predetermined weight; and using the measurement output to determine information relating to the mass of the semiconductor wafer. Also discloses is a corresponding weighing device for determining information relating to the mass of a semiconductor wafer.