A system and method for weighing of items such as mailpieces in the presence of external vibration such as ground noise. The system includes a scale system having a platform connected to a load cell, which provides an output signal to an analog-to-digital converter. The resulting digital output signal is processed by a low pass filter and analyzed by a microprocessor to determine weights of items on the platform. The microprocessor also determines postage amounts as functions of the weights and outputs these postage amounts to a postage meter. The system also includes an accelerometer and a limit detector for generating a no go signal if external vibrations exceed a predetermined limit. The microprocessor accepts a weight as valid if the external vibrations do not exceed the limit at any time while the weight is being determined and otherwise initiates an alternative weight determining method.