Monthly kWh = standby watts × device count × standby hours/day × days/month ÷ 1,000.
What counts as standby power?
Standby power is the electricity a device draws when it is not performing its main task but remains connected or ready to respond. Examples can include a television waiting for a remote signal, a game console in quick-start mode, a speaker awaiting a wireless connection, or a charger with an attached device. Actual draw varies widely by model and state.
Measure instead of assuming
When the standby load is small, a low-cost meter may struggle to measure it accurately. If you use one, follow the meter instructions and allow a stable reading. Never open mains-powered equipment to measure it. A specification is useful only if it describes the same mode you want to estimate—sleep, network standby, off-but-connected, and active idle can differ.
Practical ways to reduce avoidable standby use
- Review power settings and disable quick-start or network wake features you do not need.
- Turn off peripherals at a switched power strip when the manufacturer says doing so is appropriate.
- Do not interrupt updates, recordings, or safety functions that need a device to remain powered.
- Prioritize devices with a measured continuous load rather than assuming every plugged-in device uses a large amount of electricity.
Interpreting the estimate
The result assumes a constant standby wattage for the entered number of hours. Real devices can move between standby levels, wake for updates, or draw almost no power in a true disconnected state. The calculation also excludes any active-use energy for those devices.
Related tools and guides
For the basic relationship between watts and kWh, read Watts vs. kilowatt-hours. You can also use the Home Energy Planner to combine several devices in one estimate.