Abstract: A weighing scale that is calibratable without a calibration weight that is separate and distinct from the scale. The scale has a weighing mode and a self-calibration mode and includes a base that supports a load cell, which in turn supports a mass receiver. Electronic circuitry within the scale is configured so that, during the calibration mode, the sprung weight of the base when the scale is inverted and supported by the mass receiver can be used to calibrate the scale. This avoids the need to maintain a calibration weight external to the scale. A process of calibrating the scale includes inverting the scale during the self-calibration process and allowing the circuitry to acquire a calibration parameter that is based on the inverted sprung weight.