Electricity Cost Calculator
Turn an appliance's wattage and daily run time into its real running cost — per day, month, and year.
Watts on the label
Every appliance prints its power draw in watts on its label or nameplate — that figure plus your tariff is all you need.
Currency-agnostic
Enter the price in your own currency; the result comes back in the same currency, so it works wherever you live.
How much does it cost to run an appliance?
From watts to a running cost
A device's running cost depends on three things: how much power it draws (watts), how long it runs each day (hours), and what you pay for electricity (price per kilowatt-hour). Multiply the power by the run time to get the energy used, then multiply that energy by your price to get the cost. A 100 W bulb left on for five hours uses just half a kilowatt-hour a day — but a 2,000 W kettle reaches the same energy in only fifteen minutes.
Enter the wattage, the hours per day, and your price per kWh to see the daily, monthly, and yearly cost.
Convert the power to kilowatts by dividing the watts by 1,000, multiply by the hours run each day to get the energy in kilowatt-hours, then multiply by your price per kWh.
Cost = (watts × hours ÷ 1000) × price per kWhThe monthly cost simply multiplies the daily cost by 30, and the yearly cost multiplies it by 365. Because the price is whatever you type in, the answer is always in your own currency — there is no hidden exchange rate or assumed tariff.
Suppose you run a 100 W device for 5 hours a day at a price of 0.30 per kWh.
Convert power to kilowatts
100 ÷ 1000 = 0.1 kW.
Find the daily energy
0.1 kW × 5 hours = 0.5 kWh per day.
Apply your price
0.5 kWh × 0.30 = 0.15 per day — about 4.50 a month and 54.75 a year.
The wattage is the number that matters most: find it on the appliance's label, nameplate, or power supply, where it is printed as "W" or "watts". High-power, short-burst devices like kettles and toasters cost little overall because they run only minutes a day, while modest-wattage devices left on around the clock — fridges, routers, set-top boxes — quietly dominate a bill. Standby power adds up too: a device drawing a few watts while "off" still runs 24 hours a day, so enter its standby wattage and 24 hours to see the yearly cost of leaving it plugged in.
The arithmetic is exact, but it rests on a few simplifying assumptions.
Constant power and a flat price
The calculator assumes the appliance draws its rated power the whole time it runs, but many devices cycle on and off (a fridge) or vary their draw (a washing machine across its program), so real energy use can be lower. It also treats your price as a single flat rate; standing charges, tiered tariffs, time-of-use rates, and taxes are not included. Use the result as a solid estimate, then check your actual bill for the precise figure.