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Works with any currency. Pick a preset appliance or enter custom watts.
Electricity Cost Calculator
Enter an appliance's power in watts, how many hours a day it runs and what you pay per kilowatt-hour. You get the energy it uses per day, the running cost per day, per month and per year, and the total for any number of days.
-Energy per day
-Cost per day
-Total for these days
-Cost per month (30 days)
-Cost per year (365 days)
The formula
- Energy per day (kWh) = watts ÷ 1000 × hours per day.
- Cost = energy (kWh) × your rate per kWh.
Multiply the daily cost by 30 for a month, and by 365 for a year.
Worked example
A 100 W bulb burning 5 hours a day uses 100 ÷ 1000 × 5 = 0.5 kWh per day. At 0.20 per kWh that costs 0.5 × 0.20 = 0.10 per day, about 3.00 per month and 36.50 per year.
How to find your rate
Look at your electricity bill for the energy or supply charge per kWh. Delivery and other fees often sit on top, so the truest per-kWh number is the total bill divided by the total kWh used that month. Use that all-in figure for the most honest estimate. Many homes pay between 0.10 and 0.35 per kWh.
Watch out for standby power
TVs, chargers and game consoles draw a few watts even when switched off. A 5 W standby load running all day costs about as much as a 120 W TV running for one hour. Add standby watts to the watts field, or check with a plug-in meter, to catch these hidden costs.
Planning estimate only. Results use the list prices shown and may differ from your actual bill. Terms
Frequently asked questions
How do I find my kWh rate on my bill?
Look for the energy or supply charge line, quoted per kWh. For an all-in number, divide your total bill by the kWh used that month.
What uses the most electricity in a home?
Heating and cooling win by far. A space heater or air conditioner draws 1,500 to 2,000 W, ten times a TV and over two hundred times an LED bulb.
What is the difference between watts and watt-hours?
Watts measure power, the rate of use right now. Watt-hours measure energy, power times time. A 100 W bulb running for 5 hours uses 500 watt-hours, or 0.5 kWh.
Is this estimate exact?
It is close but not exact. Thermostat cycling, standby draw and tiered rates all move real bills up and down. Treat the result as a planning estimate, accurate to roughly 10 to 20 percent.
Do I need to know the exact wattage of my appliance?
The label or rating plate on the back of most appliances lists watts. For fridges and washing machines the average draw matters more than the peak, so the presets are reasonable starting points.