About the Electricity Cost Calculator
This calculator turns an appliance's power rating into a running cost. Enter the watts printed on the label, the hours it runs each day and your price per kilowatt-hour, and you get the energy used in kWh and the cost per day, per month and per year. Tap a typical appliance to fill in the power, choose any currency symbol, and type hours as 2, 1.5 or 1:30. You can also compare with a newer appliance to see the yearly saving. The result is an estimate from the label wattage. Refrigerators and air conditioners switch on and off, so their real average is lower, and the tool ignores standby power, fixed charges, taxes and tiered or time-of-day prices.
Updated September 2026
How to use the Electricity Cost Calculator
- 1Tap a typical appliance, or type its power in watts or kilowatts.
- 2Enter the hours it runs per day, such as 2, 1.5 or 1:30.
- 3Check the days per month and type your price per kWh from your bill.
- 4Read the energy and cost per day, month and year.
- 5Switch on the comparison to see the saving from a newer appliance, then copy the summary.
The formula: watts, hours and price
Cost = watts ÷ 1,000 × hours × price per kWh. The first part converts watts into kilowatts, the second gives kilowatt-hours, and the last converts energy into money. The month figure multiplies the daily energy by the days you enter, and the year figure always uses 365 days.
The tool checks each field before it shows a result. Hours must lie between 0 and 24, days between 1 and 31, and the price cannot be negative.
Finding your price per kWh
- Check the tariff line on your latest electricity bill.
- If only totals are shown, divide the energy charge by the kWh or units used.
- Ignore fixed monthly charges: they are the same whatever you switch on.
- With tiered prices, use the rate of the tier your extra use falls in.
- Try two prices to see the effect of a tariff change.
Appliances that cycle on and off
The label on a refrigerator or an air conditioner shows the power while it is running. A compressor runs only part of the time, often a third to a half of it, so the real energy is lower. Enter the average hours the compressor is really on, or use the typical wattage in the preset, which is an average for a refrigerator.
Devices with motors, heaters and thermostats behave the same way. If you have a plug-in energy meter, read the kWh over a day or two and compare with the estimate here. For the electrical side of a circuit see the Watts, Amps and Volts Calculator.
Is a new appliance worth it?
Enter the old appliance, tick the comparison box and type the power of the newer model. The yearly saving is shown in your currency. Divide the extra purchase price by that number to get the years needed to pay it back.
Efficient models are worth most when the device runs many hours a day, such as a refrigerator, a water heater or lighting. For something used a few minutes a week, the saving is small. Use Percentage Calculator to compare the difference as a percentage, or Discount Calculator when a sale price is involved.
Features
- Energy in kWh and cost per day, month and year
- Presets for nine common appliances
- Hours as decimals or clock time such as 1:30
- Any currency symbol; rupee amounts use Indian grouping
- Old versus new appliance comparison
- Copy a plain-text summary
- Runs in your browser
Frequently asked questions
How do I calculate the electricity cost of an appliance?
Multiply the power in kilowatts by the hours of use to get kilowatt-hours, then multiply by your price per kWh. A 1,000 W heater used 2 hours a day uses 2 kWh, which costs 16 at a price of 8 per kWh. The calculator does these steps and also gives the monthly and yearly totals.
What is a kWh?
A kilowatt-hour is the energy used by a 1,000 W appliance running for one hour. Electricity is billed by the kWh, which some bills call a unit. A 100 W lamp uses one kWh every 10 hours.
How much does it cost to run an air conditioner?
A 1,500 W air conditioner running 8 hours a day uses 12 kWh a day. At a price of 7.5 per kWh that is 90 a day. Real use is often lower because the compressor cycles off once the room is cool, so treat the figure as an upper estimate.
How do I find my price per kWh?
Look on your electricity bill for the rate per kWh or per unit, and divide the energy charge by the units used if only totals are printed. If your tariff has tiers or peak times, use the rate that applies to the extra units you would add.
Do standby devices cost money?
Yes, but only a little each. A TV or a charger in standby may draw 1 to 5 W all day. Enter that wattage with 24 hours to see the cost, and add it to the main appliance if you want the full picture.
How can I compare an old and a new appliance?
Tick Compare with a newer appliance and enter its power. The page multiplies the difference in watts by the same hours and price, over 365 days, and shows the yearly saving. Compare it with the purchase price to see the payback time.