Energy & cost
Electricity cost calculator
Work out energy use and its cost from your own wattage and tariff.
Result
Electricity costReady
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Enter your values and press Calculate result.Formula
kWh = W × hours × days ÷ 1,000Within this model
Constant or time-averaged input power over the entered operating hours and a single unit rate. Excludes standing charges, time-of-use changes and costs outside the entered rate. Default values are examples.
What the numbers mean
Energy is power multiplied by time. For appliances that cycle, such as a fridge, nameplate power multiplied by all elapsed hours will overstate use. Enter measured average power or the hours actually operating at the specified power.
Formula reference: Virginia Tech · Estimating energy use ↗A worked example
1,000 W × 4 hours × 30 days ÷ 1,000 = 120 kWh. At 25 p/kWh, that is £30.
Validation, precision and limitations