Appliance Running Cost Calculator

Who this is for

Anyone trying to work out what a specific appliance — a tumble dryer, electric heater, immersion heater, gaming PC, fridge-freezer, hot tub, aquarium pump, or anything else — actually costs to run, in real pounds rather than a vague sense of "it uses a lot." Useful for deciding whether to run something on a cheaper off-peak tariff, whether an upgrade would pay for itself, or just for understanding where the electricity bill is going.

Where do I find the wattage?

Check the rating label on the appliance itself (often on the back or base), the box or manual, or a plug-in energy monitor if you have one, which measures actual usage rather than the rated maximum. Rated wattage is usually the upper limit — some appliances, like fridges, cycle on and off and use less on average than the label suggests.

Why is the electricity price editable?

Because unit rates vary by supplier, tariff and region, and change every quarter with the Ofgem energy price cap — there is no single "correct" figure that stays accurate for long. The default of 26.1p/kWh reflects the Ofgem price cap's average direct-debit unit rate for Jul–Sep 2026; it will move again when the cap is next reviewed. For an accurate result, use the unit rate from your actual electricity bill.

Does standby power really add up?

Yes, more than most people expect. A device drawing 5W on standby for 23 hours a day, every day of the year, uses over 42 kWh a year — a small but real ongoing cost that's easy to forget because nothing is visibly "running." Switching off at the wall when not in use removes it entirely.

Is this exact, or an estimate?

It's an honest estimate based on the wattage and hours you enter. Real-world usage varies — appliances with cycles (washing machines, dishwashers, fridges) don't draw their full rated power the whole time, so a plug-in energy monitor will give a more precise reading if you want one. This calculator is best used for comparing options and getting a realistic ballpark.