Appliance Running Cost Calculator
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Any appliance's running cost comes down to two numbers: how many watts it draws and what you pay per kilowatt-hour. Enter those plus how long you use it, and this shows the cost per hour, day, month and year — useful for deciding whether that old tumble dryer or second fridge is quietly costing you real money.
Note: Assumes the appliance draws its rated power the whole time it is on. Thermostatically controlled devices — fridges, freezers, heaters — cycle on and off, so their real consumption is often a third to a half of this figure.
How this calculator works
Electricity is billed per kilowatt-hour, so the first step is converting watts to kilowatts by dividing by 1,000. Multiplying by the hours used gives the kilowatt-hours consumed, and multiplying that by your unit rate gives the cost. The calculator then scales by the days per year to give an annual figure, and works back down to per-hour, per-day and per-month costs so you can compare appliances on whichever basis makes sense.
Worked example
A 2,000 W fan heater used one hour a day at 24.5p per kWh costs 49p an hour. Run every day for a year, that is about £178.85. Cutting it to three months of winter use — roughly 90 days — brings it down to about £44. A 100 W television left on five hours a day costs around £4.47 a year by comparison, which is why heating and drying appliances dominate a typical bill.
Frequently asked questions
Where do I find an appliance's wattage?
Check the rating label, usually on the back or underneath, or the manual. It is given in watts (W) or kilowatts (kW) — multiply kW by 1,000. If only amps are shown, multiply amps by your mains voltage (230 V in the UK, 120 V in the US).
What is a typical electricity unit rate?
UK rates have hovered around 24 to 27p per kWh recently, and US rates around 16 to 18 cents, though both vary considerably by region and tariff. Your most recent bill is the reliable source — look for the per-kWh unit rate rather than the total.
Why is my fridge cheaper to run than this suggests?
Fridges and freezers cycle their compressor on and off rather than running continuously, so actual consumption is typically 30 to 50% of the rated draw. For those appliances, use the annual kWh figure on the energy label instead, or enter a reduced hours-per-day figure to approximate the duty cycle.
Does standby power matter?
Individually, very little — most modern devices draw under 1 W on standby, costing pennies a year. Collectively across a whole house it might reach £20 to £30 annually. Worth switching off at the wall, but not where the big savings are.
Which appliances cost the most to run?
Anything that heats or cools: electric heaters, tumble dryers, immersion heaters, kettles and ovens. These draw 2,000 to 3,000 W. Electronics like TVs, laptops and lighting are comparatively trivial, so focus your attention on the heating category.