Standby power cost calculator
The devices you never really switch off. Individually trivial, and together a line on your bill that nobody looks at.
Your figures
Result
- Cost per month
- $2.19
- Cost per device per year
- $3.29
- Total standby draw (W)
- 24.0
- kWh per year (kWh)
- 175
- Equivalent in washing machine loads (lavados)
- 195
By period
| Period | kWh | Cost |
|---|---|---|
| Al mes | 14.6 | $2.19 |
| Per year | 175.3 | $26.30 |
| Over 5 years | 876.6 | $131.49 |
What we assume
- A constant standby draw is assumed. In reality it varies with what the device is doing while it waits.
- The default of 2 W per device is a reasonable average for modern electronics. Older kit and set-top boxes can be far worse.
- The equivalent in washing machine loads assumes about 1 kWh per load, which is typical for a 40 °C cycle.
How it is calculated
Standby is small power multiplied by a very large number of hours. That is the whole trick: 2 W is nothing, and 2 W for 8,760 hours a year is 17.5 kWh.
kWh a year = devices x watts x hours a day x 365 / 1000
The ones that actually matter
Not the phone charger, which draws almost nothing when idle. The set-top box, the router, the games console in rest mode and the old hi-fi are the ones that add up, and some of them draw more on standby than a modern television does while you watch it.
An example
Ten devices at 2 W left on standby 20 hours a day at 0.15 per kWh come to about 22 a year — roughly 146 kWh, or 146 washing machine loads you never ran.
Frequently asked questions
Is it worth unplugging everything?
Not everything, no. Concentrate on the few devices that draw the most and that you do not need instantly available. A switched power strip does the job without unplugging anything.
How do I know what a device draws on standby?
A plug-in energy meter is the only reliable way; they are cheap. Failing that, 1 to 3 W is a fair assumption for modern electronics and 5 to 10 W for older kit.
Does a phone charger use power with nothing plugged in?
A modern one, almost none — a fraction of a watt. It is the classic example that people worry about while the set-top box quietly draws ten times as much.
Keep calculating
All tools →- Appliance running cost calculatorPower rating, hours of use and your electricity price. That is enough to know what any appliance is really costing you.
- Is it worth replacing that applianceThe efficient one costs more today and less every year. Whether that trade works out depends on numbers, and usually it is closer than the shop suggests.
Updated on 2026-08-27. Calculations run in your browser; nothing you type is sent to a server.