What is the formula for watts in a three-phase circuit?

To calculate watts in a three-phase circuit, use the formula Watts=Volts x 1.732 x Amps. The 1.732 is the square of 3 for three-phase power. Since the voltage is measured in a three-phase system from line to line, the total voltage is higher than a single-phase system which is line-to-neutral. Refer to Ohm’s Law for more ways to calculate the answer.