Electricity cost calculator
What an appliance costs to run, per hour, day, month and year.
How it works
Takes an appliance wattage, how long it runs, and your tariff, and gives the running cost over several periods.
The arithmetic is straightforward — kilowatt-hours are watts × hours ÷ 1000 — but the wattage is where estimates go wrong. The figure on the label is usually maximum draw, not typical. A fridge rated 150 W does not draw 150 W continuously; its compressor cycles, and actual consumption is often a third of the nameplate figure. Anything thermostatically controlled behaves this way.
Standby power is the one people miss. Individually trivial, collectively it commonly runs to several per cent of a household bill, because it applies every hour of every day rather than the few hours an appliance is in use.
Heating and cooling dominate almost every bill. A 2 kW heater run for four hours uses more than a laptop does in a month.
This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.
Common questions
- How do you calculate the running cost of an appliance?
- Multiply watts by hours, divide by 1,000 for kilowatt-hours, then multiply by your unit rate.
- Does an appliance draw its rated wattage all the time?
- Usually not. The label is typically maximum draw. Anything thermostatically controlled — fridges, freezers, heaters — cycles, and real consumption is often far lower.
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Sources
- Calculated on this page — At One Place