How this calculator helps
Even a small continuous electricity draw adds up when multiplied by 24 hours and 365 days. Use the measured standby watts rather than the device's full operating power.
Before you decide
Not all devices should be disconnected. Check safety requirements for medical devices, alarms, refrigerators and connected home equipment.
A practical example
A device drawing 5 W constantly uses 43.8 kWh per year. At an illustrative 28p/kWh, that is about £12.26. Three similar devices would cost about £36.79.
Frequently asked question
How can I measure standby power?
A compatible plug-in power meter may measure mains electricity draw, although very low readings can be less accurate.
What next?
Change the figures and see the estimate update instantly. For another practical check, browse our free tools library or try the daily challenge.