Electricity Cost Calculator

This power cost calculator estimates any electrical appliance's total energy usage (in kWh) and annual running cost (in dollars).

Want to skip the maths lesson? Use a plug-in power meter instead.

All you need to enter is the following:

1) Power Draw - How much power the appliance uses in Watts. You can find this on most compliance plates, as pictured here.

Power Draw in watts

2) Your Electricity Tariff in cents per kWh. You can find this on your electricity bill. Enter 25 if you don't have one handy.

3) An estimate of how often you use the appliance in hours per day, days per week, and weeks per year.

Appliance Electricity Cost & kWh Calculator:

Note: our affordable power meters do some of these calculations for you.

Example Energy Cost Calculations

Here are some example calculations for everyday appliances. Enter them in our calculator above, change the inputs, and see the impact. These examples assume an electricity tariff of 25 cents per kWh.

Appliance Usage Annual Cost
Pool Pump (1,200W) 8h/day $873.60
Fridge / Freezer (140W) 10h/day $127.40
Halogen Downlight (65W*) 6h/day $35.50
LED Downlight (7.5W) 6h/day $4.10
TV (100W on) 5h/day $45.50
TV (5W in standby) 19h/day $8.65
Ducted Air Con (4,500W) 6h/day, 24wk/yr $1134.00
Split System AC (1,100W) 6h/day, 24wk/yr $277.20
Efficient Ceiling Fan (11W) 8h/day, 24wk/yr $3.70
Clothes Dryer (2400W) 6h/wk, 50wk/yr $180.00
Fan Heater (1800W) 4h/day, 12wk/yr $151.20
Foot Mat Heater (100W) 6h/day, 12wk/yr $8.40
Electric Stove on Simmer (600W) 1h/day, 5day/wk $39.00
Billyboil Thermal Cooker (0W) 1h/day, 5day/wk $0!

*A 50W halogen light bulb loses an extra 15W in the transformer. A loss that goes down to just 1 or 2W when you switch to an LED MR16 light bulb.

How to Calculate Electricity Usage Costs

Our power calculator uses a simple formula to calculate annual energy usage and costs. Here's how it works:

Electricity Usage Per Year = (Watts / 1000) * Hours/Day * Days/Week * Weeks/Year = kWh/year

Electricity Cost Per Year = kWh/year * (cents/kWh / 100) = $/year

Two Other Ways To Calculate Your Electricity Costs

The above electricity usage calculator is quick, free, and easy to use. But it also has low accuracy (as it is based solely on estimates), and it cannot log actual energy usage over time. As the saying goes: garbage in, garbage out - so please be careful when entering your data!

For this reason, we sell several devices to help you calculate the cost of running your appliances with much greater ease and accuracy. Here are the two main types:

Plug in Electricity Cost Calculator

The Reduction Revolution Power Meter is one of our most popular products. It calculates instantaneous power usage (Watts), energy usage (kWh over time), cost, and much more.

Energy Cost Calculator App

Our range of Wireless Energy Monitors takes things a step further. They monitor your entire household's energy usage from one device!

Tips When Calculating Appliance Running Costs

The electricity cost calculator on this page is ideal for appliances with a reasonably constant power draw. Examples include LED light bulbs, heaters, pumps, motors, and portable fans.

Some appliances can be switched on 24/7 but only draw power for a portion of this time. For example, a refrigerator's compressor may only draw power for 8 to 12 hours per day. You can either estimate based on your observations or use a plug-in power meter.

For other appliances, the power usage can vary a lot. For example, a dishwasher may use 2400W when heating, 50W when pumping water, and 5W on standby. Estimating an 'average power' for these appliances can be tricky. Any device that goes through a 'cycle' is best measured with a power meter.

We think it's easier to calculate energy usage in terms of 'days per week' and 'weeks per year' rather than say 'days per year' or 'hours or year'. Strictly speaking, there are 52 weeks and one day in a non-leap year. Our calculator ignores this and bases a year on 52 weeks (364 days). For example, many devices operate for five days per week, and many people take a holiday for two weeks per year.

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