Abstract: A method and system for operational testing of a device for the balancing of a rotor in two balancing planes, wherein the device is provided with a clamping fixture, a housing, and pickups for bracing the clamping fixture in relation to the housing, the device further including a computing unit for measuring the unbalance of the rotor, and for computing and indicating a size and direction of the unbalance. The method and system further call for the device to be provided with a weight of known size mounted in the housing, the weight being removed from the housing when operational testing of the device is desired. Upon removal of the weight of known size from the housing, data corresponding to the geometric measurement of the position of the weight as mounted on the clamping fixture are automatically entered into the computing unit.