Electrical Appliances Power Consumption Calculator

Electrical appliances power consumption calculator Overview

Wondering how much power you consume in a month? Do you want to know how your power company arrives at the amount you get at the end of the month? Well! Everything is simplified for you in this electrical appliance power consumption calculator.

1. Finding Out the Power Consumption of Your Electrical Appliances Individually

Power consumption is calculated using kWh, which is kilowatt per hour. That means when calculating the amount of wattage your electrical appliances consume, the start point is finding out their wattage ratings.

When finding out the individual power consumption of your electrical appliances, you want to list all devices you have and use these three methods to find their wattages:

Check a Stamped or Tag on the Back or Bottom of Your Appliance

Most electrical appliances come stamped on their back or bottom with specific specs, including the power rating, voltage, and other specifications. It might also be a sticker or a tag.

The wattage listed here is the maximum or the starting power the appliance will draw as it starts. Some electrical devices also have the rated wattage that they consume continuously, typically half or a third of the starting wattage.

What’s more, some appliances have multiple settings that affect the amount of power they consume. So, the stated wattage won’t be able to determine the exact energy consumed by the unit.

Do Some Calculations by Multiplying Amperage by Voltage

Sometimes the manufacturer won’t list the wattage on the sticker, tag, or stamp. But you can still get it by multiplying the number of amps the appliance draws by the voltage it runs at.

Most household appliances run on either 120-volt or 240-volt. Some commercial electrical appliances run on 480-volt and above. Check the same sticker you checked earlier for this information.

Once you have the voltage and the amps, you can multiply the two to get the watts required to start the appliance.

Voltage x Amps = Watts

Use a Clamp-On Ammeter

If the information isn’t available on the devices, try finding it on the appliance’s manual, assuming you still have it.

If it’s not available, you can visit the manufacturer’s website, search for the item and check its specs. If nothing there, try contacting them and ask for these details.

There is also the option of using a clamp-on ammeter, an electrical tool that you clamp on one wire on the appliance and measure the current that flows through it.

Remember: when measuring the current the appliance draws, you may notice some electrical appliances have a high amp draw when starting and reduce significantly when it stabilizes. That’s because they have the starting power draw, about three times their smooth-running power draw.

2. Calculating the Kilowatt-Hour (kWh) Usage

You want to start by finding out how many watts each of your electrical appliances uses in a day. It’s pretty simple; all you need is to multiply the wattage rating of the device by the hours you usually use it per day. The answer you get here is the watts-hours it consumes a day.

Appliance’s Wattage (watts) x Hours Used/Day = Watt-hours (Wh)/Day

Example: Suppose you use your 120-watt TV for 5-hours per day, its power consumption in watts-hour/day would be:

120 watts x 5 hours = 600 Wh/Day

Finding the total power consumption

Do the same to all your appliances and add all the power consumptions (watt-hour/day) to get the total electrical appliance power consumption.

Converting to Kilowatt-hour/day

Remember power consumption is calculated in kilowatt-hour, not watt-hour. That means you will need to divide the answer above by 1000 to get it in Kilowatt-hour/day.

Total Appliance Power Usage (Wh) / 1000 (Wh/kWh) = Total Appliance Power Usage in kWh

You can also do it as a single step:

(Appliance’s Wattage (watts) x Hours Used/Day) / 1000 (Wh/kWh) = Appliance’s Wattage in kWh

In the example above, 120-watt TV run for 5-hours per day can consume:

120 watts x 5 hours / 1000 = 0.6kWh/day

Now that you know how many kilowatt-hours the appliance uses per day, you can estimate that usage over a month. Let’s multiply by 30 days to simulate an average month.

3. Calculating the Power Your Usage in a Month

Multiply the daily kWh usage with the 30 days to estimate your appliances’ monthly usage.

Daily Total Appliances’ Usage (kWh) x 30 (Days) = Estimated Monthly Usage in kWh/Month

You also have the option of calculating it individually. In the TV example, a 120-watt model can use

0.6kWh/day x 30 = 18kWh/Month


And that’s everything you need for an electrical appliance power consumption calculator.

As you can see, these calculations are pretty straightforward. With the usage in kWh/month, it’s much easier to estimate the amount by taking your last month’s bill, checking how much a kWh unit was going for, and multiplying it with your monthly usage. Read about generator wattage Calculator here.

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