Standby Power Calculator
Set the number and standby wattage of each device, then enter your unit rate to see the combined annual cost. Replace the starting wattages with figures for your own equipment where possible.
Use our referral link, and we'll both get £50 credit once your switch is complete.
Existing customer? Find out how you can benefit too. T&Cs apply (only one switching offer per household)
The starting watts are editable site illustrations. Replace each active row with the standby or idle draw you measured, or the figure stated by its manufacturer.
The starting unit rate is Ofgem’s price-cap rate for GB average, Direct Debit, 1 October 2026 to 31 December 2026 (Ofgem). Use the rate shown on your own tariff if you have it.
145 kWh per year
16.5 W drawn continuously. Add your unit rate above to see the cost.
What standby power is
Standby power is electricity used while a device is idle but still connected. Always-on equipment such as a router also belongs in this calculation, although its use may be intentional. To cost an appliance while it is actively running, use the appliance electricity cost calculator.
What is worth switching off?
Start with devices showing the largest annual cost, but check what function would be lost. Routers, recorders and equipment receiving updates may be doing useful work while idle. Follow the manufacturer's shutdown guidance.
A plug-in energy monitor can measure suitable equipment and is more reliable than a category estimate. Measure long enough to capture cycling or wake events; a whole-home smart-meter baseline also includes fridges, pumps and other scheduled loads.
Frequently asked questions
How much does standby power cost a UK household?
There is no single household figure. Enter the standby or idle watts for each device, multiply the combined draw by 8,760 hours to get watt-hours a year, divide by 1,000 for kWh, then apply your unit rate. The calculator performs those steps.
Which devices use the most on standby?
The answer depends on the model and operating mode. A router is normally an always-on device, while a television may have several standby modes and a console can be configured to keep network features active. Measure the relevant mode or use the manufacturer figure rather than relying on a device-category estimate.
Is it worth switching things off at the wall?
Use the measured draw and your unit rate to calculate the saving, then consider what function would be lost. A router, recorder or device performing updates may be doing useful work while idle. Follow the manufacturer’s safety and shutdown guidance rather than assuming every connected device should be switched at the wall.
Do smart plugs use power themselves?
Yes. Include the smart plug’s own measured or manufacturer-stated draw when comparing it with the load it controls. Without both figures, the calculator cannot establish whether adding the plug reduces total consumption.
Other calculators
- £Calculator
Appliance Electricity Cost Calculator
Calculate how much any household appliance costs to run per day, week, month and year.
Open calculator → - £Calculator
Electricity Bill Calculator
Calculate your electricity bill over any time period using your standing charge, unit rate and daily usage.
Open calculator → - £Calculator
Heat Loss Calculator
Estimate how much heat your home loses in kW, and the indicative heat pump size to look for.
Open calculator →
