Skip to content
ENExplore Calculators

Electricity Cost per Device

Free Electricity Cost per Device calculator with clear step-by-step results.

About Electricity Cost per Device

Counts both active and standby consumption, since a device idling at two watts for sixteen hours a day uses more than a casual estimate suggests. The standby share figure is what shows whether unplugging the device is worth the bother or whether the active hours dominate.

Formulas

Daily energy

kWh = active watts x hours / 1000 + standby watts x (24 - hours) / 1000

Annual cost

Cost = daily kWh x tariff x 365 + standing charge share x 365

Worked example

With the default values below, Electricity Cost per Device returns Annual running cost of $56.41. Change any input above and every figure here is recalculated in your browser.

Inputs used

Device power drawminimum 0 W
65 W
Hours in use per dayaccepts 0–24 h
8 h
Standby drawminimum 0 W
2 W
Electricity tariffminimum 0 $/kWh
0.28 $/kWh
Share of daily standing charge assignedminimum 0 $/day
0 $/day

Results

Annual running cost
$56.41
Monthly running cost
$4.70
Energy used per day
0.5520 kWh
Share of energy from standby
5.8% %

Step by step

  1. 1Values used
  2. 2Daily energy
  3. 3Annual cost
  4. 4Annual running cost= $56.41
  5. 5Monthly running cost= $4.70
  6. 6Energy used per day= 0.5520 kWh
  7. 7Share of energy from standby= 5.8 %

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Is standby power really significant?

Across a whole household, yes - vampire loads commonly account for 5-10% of a residential bill. For a single device it is usually small unless active use is brief.

Should I assign standing charges to a device?

Normally no, because the standing charge is payable whether or not the device exists. Leave it at zero unless you are modelling a dedicated supply.

Related Calculators

Electricity Cost per Device – Calculate Annual running cost