An automated mass comparator is a high performance comparator balance that is specially designed to carry out weight calibration in a fully automatic process. The reference weights and test weights are held in a turntable and, in accordance with a pre-programmed weighing scheme, the weight handler rotates to select the required weight and then deploys it onto the weighing pan. The weight is placed precisely onto the correct position on either the hanging weighing pan or the LevelMatic® weighing pan, depending on the magnitude of the weight. This precise placement avoids eccentricity errors. As the weight comparison process requires no human interaction, automated mass comparators deliver highly accurate weighing results with very low uncertainty. This makes them ideal for high accuracy weight calibration.