Power Consumption Calculator And Electrical Bill (+ 2 Examples)

The power consumption calculator calculates how units of electricity (kilowatt-hours or kWh) a device draws per hour, per day, per week, and per month.

In the 2 examples below, you will also find how to calculate the electrical bill (cost of running an electric-powered device), using the average price of electricity ($0.1319 per kWh).

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Power consumption (per hour)

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Power consumption (per day)

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Power consumption (per week)

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Power consumption (per month)


Here is how many watts do common household electric-powered devices use.

Electricity Bill Calculation

Electric consumption depends on only one thing: the power of a device. On a specification sheet, you will find power or wattage (expressed in Watts).

The power consumption calculator above calculates how many kWh a certain device draws. For example, a 1,000 W device draws this many kWh if running for a certain period of time:

We can calculate how much impact this will have on our monthly electricity bill. For that, we need to know the price of electricity. Let’s presume that we run a 1,000 W air conditioner continuously for 1 month, with the average price of electricity being $0.1319 per kWh.

In the monthly bill, we will have to pay for 360 kWh of electricity. Here is how we can calculate the monthly electricity bill:

Electricity Cost = 360 kWh * $0.1319/kWh = $47.48

In short, running a 1,000 W unit continuously for a month will, on average, cost about $50.

Let’s look at the 2 examples where we will estimate electricity usage:

Example 1: Electricity Usage Of 500W Washing Machine Running For 3 Hours

How much electricity will average wash use? Let’s presume that we have a 500W washing machine that runs for 3 hours. Just plug the 500W in the power consumption calculator above and we get:

calculation on electricity usage

We see that the 500W washing machine uses 0.5 kWh per hour. In 3 hours, that is 1.5 kWh. To get the dollar amount, we need to multiply electric consumption with the cost of electricity. If we presume $0.1319 per kWh electricity cost, one wash will cost us:

Electricity Cost = 1.5 kWh * $0.1319/kWh = $0.20

Example 2: Power Consumption Of A Big 3,000W Air Conditioner Per Month

Summers can be hot. Let’s presume we install a 3,000W mini-split air conditioner (3,000W equals to about 30,000 BTU). We will calculate how much will running such a device cost per month if we have it turned on 24 hours per day. Realistically, we run an AC unit for about 8 per day, and we’ll calculate electricity expenditure for that as well.

Let’s use the electricity usage calculator above:

We see that every hour, a 3,000W device uses 3 kWh of electric energy. Running it for a whole month will burn 2,160 kWh of electricity. Let’s calculate the cost of that:

Electricity Cost = 2160 kWh * $0.1319/kWh = $284,90

As we can see, running it for 24 hours per day will end up in a $284,90 increase in our monthly electricity bill. Realistically, however, we use it 8 hours per day which will cost us less than $100 per month.

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