Kilowatts to Kilowatt Hours (kW to kWh) Conversion Calculator

To convert kilowatts to kilowatt hours, the formula is kilowatt hours = kilowatts x hours. For example, if you have a 7 kilowatt AC unit and it runs for 2 hours, the calculation would be 7 kW x 2 hours = 14 kWh.

Kilowatts to Kilowatt Hours Conversion Calculator

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kilowatt hours
Conversion formula: kWh = kW × hrs

Or would you rather convert kilowatt hours to kilowatts?

Kilowatts to Kilowatt Hours Conversion Table

Here is a conversion table converting common values of kilowatts to kilowatt hours, over a duration of 1 hour and 1 day.

Kilowatts (kW)Kilowatt Hours (kWh) @ 1 hourKilowatt Hours (kWh) @ 1 day
1 kW1 kWh24 kWh
2 kW2 kWh48 kWh
3 kW3 kWh72 kWh
4 kW4 kWh96 kWh
5 kW5 kWh120 kWh
6 kW6 kWh144 kWh
7 kW7 kWh168 kWh
8 kW8 kWh192 kWh
9 kW9 kWh216 kWh
10 kW10 kWh240 kWh
11 kW11 kWh264 kWh
12 kW12 kWh288 kWh
13 kW13 kWh312 kWh
14 kW14 kWh336 kWh
15 kW15 kWh360 kWh
16 kW16 kWh384 kWh
17 kW17 kWh408 kWh
18 kW18 kWh432 kWh
19 kW19 kWh456 kWh
20 kW20 kWh480 kWh

Note: Don't see the values you're looking for in this table? Use our kW to kWh calculator at the top of this page to calculate them for your specific scenario.

Kilowatts vs Kilowatt Hours: What's the Difference?

Kilowatts (kW) and kilowatt hours (kWh) are both units related to power, energy, and electricity, but they refer to different concepts.

A kilowatt is a measure of how much power is being used or produced at a given moment.

A kilowatt hour is a measure of how much energy has been used or produced over a period of time.

I think the most helpful analogy for understanding the difference between kilowatts and kilowatt hours is to consider the difference between speed and distance. Think of kilowatts as the speed at which you're driving a car, while kilowatt hours is the total distance you've traveled.

If you drive a car at a speed of 50 mph for 1 hour, you've traveled a distance of 50 miles (50 mph × 1 hr = 50 mi).

Likewise, if a device uses 2 kilowatts of power for 10 hours, it has used 20 kilowatt hours of energy (2 kW × 10 hrs = 20 kWh).

How to Convert Kilowatts to Kilowatt Hours (kW to kWh)

To convert kilowatts to kilowatt hours, simply multiply kilowatts by hours.

Conversion formula: kilowatt hours = kilowatts × hours

Abbreviated formula: kWh = kW × hrs

Example

Let's say your water heater uses 1.5 kilowatts and runs for around 5 hours per day.

Here's how you'd calculate its daily energy consumption in kilowatt hours:

1.5 kW × 5 hrs = 7.5 kWh

Your water heater consumes 7.5 kilowatt hours of electricity per day.

Why Convert Kilowatts to Kilowatt Hours?

There are 2 main reasons to convert kilowatt to kilowatt hours:

  1. To estimate how much energy a device or appliance uses
  2. To estimate how much energy a power source, such as solar panel system or generator, produces

1. Estimating Energy Usage of an Appliance

Your power bill is based on how many kilowatt hours you use per month. So calculating an appliance's energy usage in kilowatt hours helps you determine how much it costs to run that appliance. (I talk more about how to calculate this in the next section.)

Alternatively, if you're building an off-grid solar or electrical system (such as in a boat or RV), estimating your system's energy usage in kilowatt hours will help you size your battery bank. This is called an energy audit, and you can use our solar load (kWh) calculator to help with that.

2. Estimating Energy Production of a Power Source

Converting kilowatts to kilowatt hours is also useful when sizing a power source, such as a generator or solar panel system.

Let's say you're considering putting solar panels on your roof. You get a quote for a 5kW solar system, and the solar installer estimates that the system will operate at max power output for around 5 hours a day on average.

Using these values, you could estimate the system's daily energy production by multiplying kilowatts by hours:

5 kW × 5 hrs = 25 kWh

So, on an average day, you'd expect your system would generate around 25 kilowatt hours. (This scenario is extremely simplified and given just for illustrative purposes.)

How to Calculate Kilowatt Hours for an Appliance

To estimate an appliance's energy usage in kilowatt hours, you'll need the following info:

  1. Its power consumption in watts or kilowatts
  2. How many hours it runs for

For instance, let's say you're trying to calculate how many kilowatt hours your dryer uses.

To find its power consumption, you'll need to look at its label or in the product manual, or search for it online. Mine didn't have its wattage listed anywhere on the label, so I Googled the model name plus the word "wattage" and learned that it uses 4.5 kilowatts.

Note: If your appliance's power consumption is listed in watts (W) rather than kilowatts, you can convert watts to kilowatts by simply dividing by 1000. Say my dryer's power consumption had instead been listed as 4500 watts; I could've just divided 4500 ÷ 1000 to get 4.5 kilowatts.

Great -- I know my dryer's power draw in kilowatts.

Next I need to figure out how many hours it runs for. You could of course time how long it takes to dry your clothes and get exact numbers, but I'll keep it simple and estimate that each dry cycle takes on average 30 minutes.

To calculate the kilowatt hours used each time you run your dryer, you'd multiply its power usage in kilowatts by the runtime in hours:

4.5 kW × 0.5 hrs = 2.25 kWh

So, your dryer uses around 2.25 kilowatt hours of electricity every time you run it.

You can go one step further and estimate how much money it costs to run your dryer by multiplying its kilowatt hours by the cost of electricity in your area. Your cost per kilowatt hour is listed in your power bill.

For instance, where I live, electricity costs $0.11 per kWh. To estimate how much it costs to run my dryer once, I multiply its electricity usage by my cost of electricity.

2.25 kWh × $0.11/kWh = $0.2475

So, in this example, it would cost around $0.25 every time I run my dryer.

How to Convert Watts to Kilowatt Hours (W to kWh)

Some devices and appliances list their power consumption in watts (W) rather than kilowatts. 1 kilowatt is equal to 1000 watts. So, to convert watts to kilowatt hours, you multiply watts by hours and then divide by 1000.

Conversion formula: kilowatt hours = watts × hours ÷ 1000

Abbreviated formula: kWh = W × hrs ÷ 1000

Calculator: Watts to Kilowatt Hours Conversion Calculator

Example

Let's say you have an LED lightbulb that consumes 10 watts.

This 60-watt equivalent LED lightbulb actually consumes only 10 watts.

This bulb is in a lamp that you leave on for an average of 6 hours a day. How many kilowatt hours is the lamp using each month?

Well, first we need to calculate how many hours the bulb is on each month.

6 hrs × 30 days = 180 hrs per month

So the bulb is on for 180 hours every month. Now we can calculate its monthly energy consumption in kilowatt hours.

10 W × 180 hrs ÷ 1000 = 1.8 kWh

Your lamp uses 1.8 kilowatt hours of energy every month. In the grand scheme of things, that's paltry compared to the energy consumption of other appliances in a typical house. AC units, water heaters, fridges, and dryers are usually the real energy hogs.

How to Convert Kilowatt Hours to Kilowatts (kWh to kW)

Need to convert the other way?

To convert kilowatt hours to kilowatts, divide kilowatt hours by hours.

Conversion formula: kilowatts = kilowatt hours ÷ hours

Abbreviated formula: kW = kWh ÷ hrs

Example

Let's say your house uses on average 21 kWh per day. What is your house's average power usage in kilowatts?

To calculate this, you'd simply divide kilowatt hours by the number of hours in a day:

21 kWh ÷ 24 hrs = 0.875 kW

So, your house is using on average 0.875 kilowatts, or 875 watts.

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Alex Beale
Alex Beale
Alex Beale is the founder and owner of Footprint Hero. As a self-taught DIY solar enthusiast, Alex has spent 4 years producing educational solar content across YouTube, TikTok, Instagram, and the Footprint Hero blog. During that time, he's built Footprint Hero to over 7 million blog visits and 18 million YouTube views. He lives in Tennessee.