Electricity Bill Calculator

Electricity Bill Calculator turns an appliance's wattage into money: what it costs per hour, per day, per month and per year at your own unit rate.

The arithmetic is simple and the units are where people trip. Electricity is billed by the kilowatt-hour, which is a thousand watts drawn for one hour. An appliance rated at 2,000 watts run for 30 minutes uses one kilowatt-hour. So the calculation is watts divided by a thousand, multiplied by hours, multiplied by your price per unit. Everything else on this page is that formula projected over longer periods.

The results are often surprising in both directions. A device that draws very little but runs constantly can cost more over a year than something powerful used occasionally: a 5W router left on all year uses more than a 2,000W kettle boiled twice a day. Running the numbers for several appliances is usually more informative than any general advice about which ones to worry about.

The rate is yours to enter, because it varies by country, supplier and tariff, and often by time of day. Look at a recent bill for the price per kWh. If you are on a time-of-use tariff, run the calculation separately for peak and off-peak hours, since that difference is frequently larger than anything you would achieve by changing the appliance.

Everything is worked out inside your browser. Nothing you enter is uploaded, logged or stored, which matters for the financial calculators in particular: the figures you put into them are nobody else's business.

• Cost per hour, day, week, month and year
• Energy used in kWh alongside the money
• Watts, kilowatts or amps and volts as input
• Compare several appliances in one list
• Standing charge included if you want the full bill picture
• Any currency and any rate
• Runs in your browser

The electricity bill calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

• Finding out what the tumble dryer actually costs
• Deciding whether an old appliance is worth replacing
• Checking a bill that came in higher than expected
• Working out the cost of leaving something on standby
• Comparing two appliances before buying