Electricity Cost Calculator

How to calculate electricity cost

The formula is simple: watts × hours used ÷ 1,000 = kilowatt-hours (kWh), and kWh × your price per kWh = cost. A 900-watt window air conditioner running 8 hours a day uses 7.2 kWh a day; at $0.17 per kWh, that is about $1.22 a day, or roughly $37 a month. The calculator above does this for you, multiplies it out to a month and a year, and estimates the carbon emissions from your country’s average electricity grid.

Your price per kWh is on your electricity bill (look for “unit rate” or “energy charge”). If you are on a time-of-use tariff, use the rate for the hours the appliance actually runs.

How much does it cost to run common appliances?

Wattages vary widely between models, and fridges, air conditioners and heat pumps cycle on and off, so their average draw is lower than their rated power. The most accurate way to know is to measure: an energy-monitoring smart plug shows real watts and kWh for anything you plug into it.

How to cut your electricity bill

Start with the biggest numbers. Heating and cooling are usually the largest loads: a ceiling fan costs a fraction of an air conditioner, and a heat pump delivers two to three times more heat per kWh than a space heater (see are heat pumps worth it?). Swap remaining old bulbs for LEDs, switch off devices that sit on standby, and run washing and dishwashing on full loads.

Electricity and carbon emissions

The same kWh has a very different climate impact depending on where you live. Norway and France run mostly on hydro and nuclear power at well under 50 g CO₂e per kWh, while coal-heavy grids such as South Africa, India and Indonesia emit close to 700 g. That is why the calculator asks for your country: cutting electricity use saves the most carbon where the grid is dirtiest, and switching to clean electricity matters as much as using less.