Home Calculators Power Usage Calculator

Power Usage Calculator

Knowing the cost of running an electrical appliance is useful, and easy with this power usage calculator.

You need to know three things:

1. Cost of one kilowatt hour (kWh) of electricity. This should be on your power bill.

Example: your electricity costs 24.5 cents/kWh – enter $0.245 in the calculator

You can still use this calculator even if your currency is not dollars – just enter the cost per kWh in your currency and ignore the $ sign.

2. The power used by the appliance. The power rating of an appliance is normally written on a sticker, label or plate (often at the back or under the appliance). It is also common these days for manufacturers to state the standby power of their appliances, although you may need to find the detailed specifications to read this.

The stated power of a light bulb might be 60 watts, or an electric heater might be 1000 watts.

You can also use a simple power meter. Here is a sample of power meters available from Amazon in the USA or UK or Australia. Disclosure: If you buy through these Amazon links Geoff receives a small commission from each sale.

3. How many hours the appliance is used in a day. This is an estimate of the average hours used. To calculate standby power, enter 24.

Note: Some appliances like heaters, fridges and air conditioners do not use their rated power all the time they are on. These appliances normally have a thermostat allowing them to turn off when the desired temperature is reached. Therefore the hours of use entered in the calculator can be less than the actual hours of being on.


Further reading

Please Note: During the Covid-19 pandemic I'm busy with a number of streaming projects, and have very limited time to attend to this website. I'm currently taking up to a week to answer questions. Sorry for any inconvenience.