This super simple amps to watts calculator will calculate watts as long as you know the voltage and ampere numbers. Enter the voltage and the amps below to calculate wattage, and then read on to understand how this simple calculation works!

Amps to Watts Calculator

Enter the voltage and amps to calculate watts below. If you don’t know both of them, follow on after the calculator to learn more!



The Formula

The amps to watts calculator is based on Watt’s Law. The formula is super simple and looks like this: P = V * I

  • P = Power (or wattage)
  • V = Voltage
  • I = Current (or amps)

To put this in perspective and make it simple if you have vacuum cleaner that plugs into a 120 volt outlet and is rated at 12 amps, the calculation would look like this: 120 * 12 =  1440 watts.  It’s that simple!

Another example. You have a car radio that operates at 12 volts with a current of 1.5 amps.  12 * 1.5 = 18 watts.

It Works with Any Combination

amps to watts calculator using watt's law Now get ready to have your mind blown! The amps to watts calculator works with just any of the two numbers. You only need two to find other other digit.

  • Watts (P) = Voltage(V) * Current (I)
  • Voltage (V) = Watts (P) / Current (I)
  • Current (I) = Watts (P) / Voltage (V)

Another super easy example: If you know your heater is 1500 watts and is plugged into a 120v US outlet, then we can use this formula: I = V * P

The calculation is 1500 watts / 120 volts = 12.5 amps.

We have a fantastic tutorials on voltage and amperage. Check them out!