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Standby Power Calculator

What devices left on standby cost you each year — the so-called vampire load.

Enter values

Results update as you type.

Result

Annual standby cost

$49.06

Switching devices off at the socket, or using a smart strip, removes almost all of this.

Annual energy wasted
175.2 kWh
Monthly cost
$4.09
Continuous load
24 W
CO₂ per year
40.8 kg
Over 10 years
490.56

About the Standby Power Calculator

What devices left on standby cost you each year — the so-called vampire load.

Also known as: vampire power calculator, phantom load, standby cost, always on power.

How to use this calculator

  1. Enter number of devices, average standby draw, hours on standby per day, cost per kwh.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

kWh = devices × watts × hours × 365 ÷ 1000

Worked example

Using the values pre-filled in the calculator above:

  • Number of devices = 12
  • Average standby draw = 2 W
  • Hours on standby per day = 20
  • Cost per kWh = 0.28

the calculator returns:

  • Annual standby cost: 49.06
  • Annual energy wasted: 175.2 kWh
  • Monthly cost: 4.09
  • Continuous load: 24 W