By Alan Sembera – Updated March 24, 2022
Converting millivolts to amperes is a quick task when you know the device’s power rating in watts. Once you have both values, the classic power equation—Watts = Volts × Amps—lets you solve for the current. Because the equation uses volts, you’ll first convert millivolts to volts.
Locate the power rating on the device itself or in its user manual. This figure is expressed in watts (W) and represents the electrical power the device consumes.
Divide the millivolt reading by 1,000. Each volt contains 1,000 millivolts, so a measurement of 2,500 mV becomes 2.5 V.
Divide the wattage by the converted voltage: Amps = Watts ÷ Volts. The result is the circuit’s amperage.
Example: A 50‑W appliance powered by a 2,500‑mV source draws 20 A (50 W ÷ 2.5 V = 20 A).
