Watts and kilowatt-hours
Divide watts by 1,000 to get kilowatts. Multiply by hours to get energy in kilowatt-hours, then multiply by the unit price in pounds. A 2,000 W heater running continuously for two hours uses 4 kWh.
Rated power is not always actual consumption
Fridges, heat pumps and other controlled appliances switch or vary their output. Multiplying the maximum rating by every hour can exaggerate use. A suitable energy monitor or the appliance’s measured consumption gives a better input.
Separate standing charges
Standing charges belong to the household bill, rather than to the incremental cost of one appliance. This tool excludes them. It also assumes one unit rate; split time-of-use tariffs into separate calculations.
Common questions
Does this use today’s price cap?
No. Enter your own tariff. The starting unit rate is an illustration and is not a quoted current tariff.
Sources & methodology
This page uses original budgeting guidance and transparent arithmetic. Example prices are chosen illustrations, not a survey of UK market prices. Replace them with written quotations.
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