Electricity Cost Calculator
See what an appliance costs to run each day, month and year.
About this tool
Multiplies the power rating in watts by the hours of use to get kilowatt-hours (kWh), then by your price per kWh. Use the price from your electricity bill, including any taxes, for the most accurate result. Everything is worked out in your browser.
Every appliance has a power rating in watts, usually printed on a label or in the manual. Combine it with how long you use the appliance and the price you pay per kilowatt-hour (kWh) to see exactly what it costs to run. Use it to compare a heater with an air conditioner, check what a pool pump adds to your bill or decide whether a more efficient fridge pays for itself.
How to use the Electricity Cost Calculator
- Enter the power rating in watts (1 kW = 1 000 W).
- Enter how many of the appliance you run, and for how many hours a day and days a week.
- Enter your price per kWh from your electricity bill and choose your currency symbol.
- Read the cost per day, month and year and the energy used.
A 2 000 W heater for 3 hours a day
A 2 000 W heater uses 2 kW, so 3 hours a day is 2 × 3 = 6 kWh. At 0.30 a kWh that costs 1.80 a day. Used every day, that is 6 × 7 × 52 = 2 184 kWh a year, which costs 655.20 a year or about 54.60 a month. Running it only on weekdays (5 days a week) brings the yearly cost down to 468.
Watts, kilowatt-hours and your bill
Watts measure how fast an appliance uses energy; kilowatt-hours measure how much it has used. Running a 1 000 W appliance for one hour uses 1 kWh, and so does a 100 W appliance for ten hours. Your bill charges per kWh. The label figure is usually the maximum power, so appliances with a thermostat or motor, such as fridges, ovens, heaters and air conditioners, often use less on average because they switch on and off. For those, an annual kWh figure from the energy label or a plug-in energy meter gives a better estimate. Many suppliers also charge a fixed daily fee or different rates by time of day or by how much you use, which this calculator does not include.
Frequently asked questions
How do I convert watts to kWh?
Multiply the watts by the hours of use and divide by 1 000. A 60 W bulb on for 5 hours uses 60 × 5 ÷ 1 000 = 0.3 kWh.
Where do I find my price per kWh?
On your electricity bill or your supplier’s tariff page. Use the rate including taxes. If you have stepped or time-of-use rates, use the rate you pay most often.
Where do I find an appliance’s wattage?
Look for a rating plate or sticker on the back or base, or in the manual. It may be shown in kW: 1.5 kW is 1 500 W.
Why is my real bill different?
Thermostats and standby use change how much energy appliances actually draw, and bills often add fixed charges. Treat the result as a guide.