A method for determining a weight of material being emptied from a container is shown. The container is lifted to and lowered from an emptying position in a lift empty and lower cycle by an arm which has at least two sensors mounted on it. The method includes selecting at least one measurement position, calibrating the sensors by recording the respective outputs from each of the sensors for both an empty arm and for an arm lifting and lowering a calibrating weight. The outputs recorded for the calibrating weight can then be subtracted from the outputs recorded for the empty arm. Then, an unknown load can be lifted emptied and lowered with the output of the sensors being similarly recorded at the measurement position. By subtracting the output recorded during the lifting portion of the cycle for the unknown load from the output recorded during the lowering cycle for the unknown load a change in output far each sensor at the measurement position can be obtained. The change in output of the sensors can then be compared to the change in output recorded for the calibration step and a weight value calculated. In another aspect of the present invention an apparatus is disclosed having at least two sensors mounted to a sensing portion of an arm. Output from each sensor i.s independently recorded and used in obtaining calibration values and actual weight values.