Zener Diode Calculator Enter value and click on calculate. Relevant results will appear at the bottom. Maximum Input = Max supply to the zener. Minimum Input = Lowest possible supply to the zener, which cannot be lower than the preferred output voltage... Enter the selected values: Maximum Input Voltage: Volts Minimum Input Voltage: Volts Output Voltage: Volts Load Current: MAmperes Results: Resistance: Ohms Watts Zener: Volts Watts