How to calculate electricity cost
- Enter your electricity price per kWh from your bill or tariff, and your currency symbol.
- Add appliances from the list. Each starts with a typical wattage and daily use; edit them to match yours. The wattage is on the label or in the manual.
- See the cost of each appliance per month and the total per day, month and year in money and kWh.
From watts to money
Energy use is power × time. An appliance drawing 1,500 watts (1.5 kW) for 3 hours uses 4.5 kilowatt-hours (kWh). At 0.30 per kWh that costs 1.35 a day, about 41 a month and 493 a year. The calculator does this for each row and adds them up, using an average month of 30.4 days.
The wattage on the label is usually the maximum. Appliances that cycle on and off, such as fridges, freezers, heaters with thermostats and air conditioners, use less on average; that is why the fridge-freezer preset uses an average draw of 50 W rather than its compressor rating. For the most accurate numbers, use a plug-in energy monitor for a day or two, or check the yearly kWh on the energy label and divide by 365. Devices on standby also add up: ten gadgets at 2 W each use about 175 kWh a year.
Your appliance list is saved in this browser only, so it is there next time; nothing is uploaded.
How much does it cost to run a space heater?
A 1,500 W heater uses 1.5 kWh per hour: at 0.30 per kWh, 45 cents an hour while it heats at full power.
Where do I find my price per kWh?
On your electricity bill or your supplier's tariff page. Include taxes; ignore fixed daily charges.
What is a kilowatt-hour?
The energy used by a 1,000 W device in one hour. It is the unit on your bill.