Electricity Bill Estimator

About this tool

Estimate your monthly electricity bill by listing each appliance with its power in watts, the hours it runs each day and the days it is used each week. Enter your own price per kWh from your bill, plus any fixed charge and tax, and see which appliances use the most. Entries stay in your browser.

How it works

• Energy per month for one appliance is watts divided by 1,000, times hours per day, times days per week divided by 7, times 30.44 days, times how many you have.
• 30.44 is the average length of a month: 365.25 days divided by 12.
• Energy cost is all the kWh times your price per kWh. The fixed charge is added, and then the tax percentage is added on top of both.
• The cost per month next to each appliance includes tax but not the fixed charge. Biggest users ranks appliances by kWh and shows the share of each.

Common questions

Where do I find the wattage of an appliance?

Look at the label or plate on the back or bottom of the appliance, or in its manual. It is often shown in W or kW, and 1 kW is 1,000 W. A plug-in power meter shows the real figure while it runs.

Why is my real bill different from the estimate?

Fridges, heaters and air conditioners switch on and off with their thermostat, so they rarely draw full power every hour. Your tariff may also have steps or time-of-day prices. Enter the hours an appliance really runs and your average price.

Which price per kWh should I enter?

The one on your own bill or tariff. If the price changes with how much you use, divide the energy part of a recent bill by the kWh on it to get an average. The 0.25 filled in at the start is only a placeholder.