Abstract: Tare adjusting apparatus for a computing scale includes a tare adjustment knob for establishing the no-load reference position of the scale and thus compensating for the weight of the packaging material of the product being weighed. A sensing circuit includes a switch for detecting when the tare adjustment knob is adjusted or set to zero and an oscillator circuit for determining when the tare adjustment knob is manually touched. A tare warning lamp is controlled by a control circuit which is responsive to the sensing circuit for lighting the tare warning lamp if the operator should touch the tare adjustment knob during a weighing operation. The tare warning lamp is lit before each weighing operation by the control circuit and is extinguished only when the tare adjustment knob is adjusted or set to zero. Thus the operator is reminded that the proper tare setting may need to be reset after each weighing operation.