Enter the peak wattage into the calculator to convert the value into the root mean square wattage (RMS Wattage). This calculator can also determine the peak wattage given RMS wattage.

RMS Wattage Formula

The following formula is used to calculate the root mean square wattage:

WRMS = PW * .707
  • Where WRMS is the root mean square wattage
  • PW is the peak wattage

To calculate RMS wattage, multiply the peak wattage by a value of .707.

Further peak wattage can be calculated from the peak voltage and current.

PW = PV * I 
  • Where PV is the peak voltage
  • I is the current in amps

RMS Wattage Definitoin

What is RMS Wattage?

An RMS value, or in this case, wattage, is a measure of the root mean square of the wattage in a sinusoidal circuit.

Example Problem

How to calculate RMS Wattage?

First, determine the peak wattage. This can be calculated from the peak voltage and current of the system. In this case, the peak voltage is 40 volts and the current is 40 amps.

Multiply these together yields the peak wattage:

PW = 40 * 40

PW = 160 Watts

Next, use the formula above to calculate the RMS wattage:

WRMS = PW * .707

WRMS = 160 * .707

WRMS = 113.12 watts