Enter the power consumption in standby mode, the time the device is in standby mode, and the rate of electricity into the calculator to determine the phantom load. This calculator can also evaluate any of the variables given the others are known.

Phantom Load Formula

The following formula is used to calculate the phantom load.

PL = P * T * R

Variables:

  • PL is the phantom load (kWh)
  • P is the power consumption in standby mode (Watts)
  • T is the time the device is in standby mode (hours)
  • R is the rate of electricity (kWh)

To calculate the phantom load, multiply the power consumption in standby mode by the time the device is in standby mode. Then multiply the result by the rate of electricity. The result will be the phantom load in kilowatt-hours (kWh).

What is a Phantom Load?

A Phantom Load, also known as standby power or vampire power, refers to the energy consumed by electronic devices when they are turned off or in standby mode. This includes appliances like televisions, computers, chargers, and kitchen appliances that continue to draw power even when they are not actively in use. It’s called a “phantom” because it’s a hidden form of energy consumption that can contribute significantly to overall energy usage.

How to Calculate Phantom Load?

The following steps outline how to calculate the Phantom Load.


  1. First, determine the power consumption in standby mode (P) in Watts.
  2. Next, determine the time the device is in standby mode (T) in hours.
  3. Next, determine the rate of electricity (R) in kWh.
  4. Next, gather the formula from above = PL = P * T * R.
  5. Finally, calculate the Phantom Load (PL) in kWh.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

power consumption in standby mode (P) = 10 Watts

time the device is in standby mode (T) = 24 hours

rate of electricity (R) = 0.15 kWh