Electricity Cost Calculator

About the electricity cost calculator

Which devices make your electricity bill big? This calculator tells you. Type the electricity price per kWh from your bill. Then add each device with its power in watts and the hours per day you use it. You see the cost per day, per month and per year, and a table that puts the devices in order — the most expensive first.

Use the Add a device list for common devices with a typical wattage (a TV, a kettle, a dryer, an air conditioner, an electric car charger and more), or add your own device. The numbers are saved in your browser, so you can come back and change them.

How to use it

• Type the electricity price per kWh — look for it on your bill
• Check the example devices, or choose another from Add a device
• For each device type the power in watts (on the label or in the manual), the hours per day, the days per week and how many you have
• Optional: type a fixed monthly charge from your bill
• Read the cost per month, per year and per day, and the table of devices

How it is worked out

kWh = watts ÷ 1,000 × hours. A 100 W TV on for 4 hours uses 0.4 kWh. At $0.17 per kWh that is 6.8 cents a day, about $2.07 a month.

Cost = kWh × price per kWh. The calculator uses 30.44 days in a month.

What devices cost to run

At $0.17 per kWh:

Heating and cooling devices, ovens and dryers cost the most. Little things that run all day — a router or a fridge — add up too.

Example

The calculator starts with a refrigerator (150 W, about 8 hours of real running a day), LED lights (6 × 10 W, 5 hours), a TV (100 W, 4 hours), a laptop (60 W, 6 hours) and a washing machine (500 W, 1 hour, 3 days a week). At $0.17 per kWh:

That is $154 a year.

Tips to lower the bill

• Switch off standby devices with a power strip
• Use LED bulbs
• Wash at 30 °C and air-dry when you can
• Set the air conditioner a little higher and the heater a little lower
• Run the dishwasher and washer when full
• Ask your supplier about a cheaper night tariff if you can move big loads

Frequently asked questions

How do I calculate the cost of running a device?

Multiply its watts by the hours, divide by 1,000 to get kWh, and multiply by your price per kWh.

Where do I find the watts?

On the label on the back or the bottom of the device, or in the manual. If only volts (V) and amps (A) are given, watts = volts × amps.

Why is my fridge listed with 8 hours?

A fridge is on all day, but the motor runs only a part of the time (about a third). The example uses the average. Use 24 hours if your device really runs all the time, like a router.

Does the calculator include taxes and fees?

It uses the price per kWh you type. If your bill has taxes or fees per kWh, add them to the price. A fixed monthly charge has its own box.

How much does it cost to charge an electric car?

Choose Electric car charger from the list, or type your charger power (often 7,000 W) and the hours of charging.

Is the result exact?

It is a good estimate. Devices use less than their label when they are not at full power. A plug-in power meter gives exact numbers.

Good to know

• Works with any currency — choose it at the top
• Your devices are saved only in this browser
• Nothing you type is sent anywhere

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