Watts to kWh Calculator – Watts to Kilowatt Hours Conversion

Welcome to our Watts to kWh Calculator, a user-friendly tool designed to simplify the conversion of power consumption from watts to kilowatt-hours. Whether you’re an individual, business, or organization, our intuitive calculator allows you to effortlessly determine the energy consumption of your electrical devices. Understanding the energy usage of your appliances is essential for optimizing efficiency and managing electricity costs. With this Watts to Kilowatt Hours Conversion tool, you can easily grasp the amount of energy consumed over time, making informed decisions for a greener and more economical future. Take the guesswork out of your energy calculations and explore the convenience of our Watts to kWh Calculator today.    

Enter power in watts: W
Enter time in hours: hr
Energy result in kilowatt-hours: kWh

What is a Watts to kWh Calculator?

A Watts to kWh (kilowatt-hours) calculator is a tool used to convert power consumption measured in watts (W) into energy consumption measured in kilowatt-hours (kWh). It helps you understand how much energy is consumed at a given power level over a specific period.

To understand the conversion, you need to know the formula for calculating energy consumption:

Energy (kWh) = Power (kW) × Time (hours)


  • Energy is measured in kilowatt-hours (kWh)
  • Power is measured in kilowatts (kW)
  • Time is measured in hours

The Watts to kWh calculator essentially performs this conversion for you. You provide the power consumption in watts, the time duration in hours, and the calculator gives you the energy consumption in kilowatt-hours.

For example, if you have a device with a power rating of 100 watts and it’s used continuously for 5 hours, the energy consumption would be:

Energy (kWh) = 100 watts × 5 hours = 0.1 kWh

Monitoring energy consumption to understand electricity usage and manage energy costs effectively is important. This is particularly useful for households, businesses, and organizations looking to be more energy-efficient and environmentally conscious.

How does this Watts to kWh Calculator work?

The Watts to kWh calculator is a tool that helps you determine how much energy an electrical device or appliance consumes over a certain period. It works by taking two inputs from you:

  1. Power in Watts: This is the electricity the device uses per second. For example, if you have a 100-watt light bulb, it consumes 100 watts of power when it’s turned on.
  2. Time in Hours: This is the duration for which the device is used. It could be the number of hours the device is turned on, or how long you want to calculate the energy consumption for.

Once you enter the power values in watts and time in hours, you click the “Calculate” button. The calculator then performs a simple mathematical calculation using the formula:

Energy (kWh) = (Power in Watts × Time in Hours) / 1000

Here’s what happens step by step when you click “Calculate”:

  1. The calculator takes the power value you entered (in watts) and the time value (in hours) you provided.
  2. It multiplies these two numbers together. For example, if you entered 100 watts for power and 5 hours for time, it would be: 100 watts × 5 hours = 500 watt-hours (Wh).
  3. Since kilowatt-hours (kWh) are a more common unit for measuring energy, the calculator then divides the result by 1000 to convert watt-hours to kilowatt-hours. In our example: 500 Wh / 1000 = 0.5 kWh.
  4. Finally, the calculator shows you the energy consumption in kilowatt-hours (kWh). In the example above, it would display “0.5 kWh” in the result box.

The calculator is handy for estimating how much energy a device uses over a specific time, helping you manage your electricity consumption and make informed decisions about energy efficiency. If you want to calculate again with different values, you can click the “Reset” button to clear the input fields and start over.

The table on watts to kWh conversion (time 1 hour)

Watts (W)Time (hours)Energy (kWh)

The table on watts to kWh conversion (Different time ranges)

Watts (W)Time (hours)Energy (kWh)

How many watts a 1.5 ton AC consumes?

The power consumption of an air conditioner is typically measured in watts (W) or kilowatts (kW). To determine how much power a 1.5-ton AC consumes, we need to know its cooling capacity and the energy efficiency ratio (EER).

1 ton of cooling is equivalent to 12,000 British Thermal Units (BTUs) per hour. So, a 1.5-ton AC would be:

1.5 tons * 12,000 BTU per ton = 18,000 BTU per hour

To convert BTUs to watts, we use the following conversion:

1 BTU/hr = 0.29307107 watts

So, for an 18,000 BTU/hr AC:

18,000 BTU/hr * 0.29307107 watts/BTU = 5275.2786 watts

Rounded off, a 1.5-ton AC consumes approximately 5275 watts (or 5.275 kilowatts) of power while running.

How many kWh is 2400 watts?

To calculate how many kilowatt-hours (kWh) 2400 watts is equivalent to, you need to know the time duration for which the 2400 watts are being used. The formula to calculate energy consumption in kWh is:

Energy (kWh) = Power (kW) × Time (hours)

Given that 1 kilowatt (kW) is equal to 1000 watts (W), we can convert 2400 watts to kilowatts:

2400 watts = 2400 / 1000 kW = 2.4 kW

Now, let’s assume the time duration is 1 hour. Plugging the values into the formula:

Energy (kWh) = 2.4 kW × 1 hour = 2.4 kWh

So, 2400 watts is equivalent to 2.4 kilowatt-hours (kWh) when used for 1 hour. If the time duration is different, you can use the formula to calculate energy consumption accordingly.

How many watts in a kilowatt hour?

Generally, there are 1,000 watts in a kilowatt-hour (kWh).

The term “kilowatt-hour” is a unit of energy that represents the energy consumed or produced by using 1 kilowatt (kW) of power for 1 hour.

Since there are 1,000 watts in a kilowatt (kW), the term “kilowatt-hour” indicates that the energy consumed or produced is equivalent to 1,000 watts used or generated for 1 hour.

Simply, if you use a 1-kilowatt (1,000 watts) device continuously for 1 hour, it will consume 1 kilowatt-hour (kWh) of electricity.

How Many Watts Are in a Megawatt?

There are 1 million watts in a megawatt (MW).

The term “megawatt” is a power unit representing one million watts. It is commonly used to measure the power capacity of large-scale electrical generation plants, industrial facilities, and other significant power systems.

So, to convert from megawatts (MW) to watts (W), you multiply the value in megawatts by 1 million:

1 megawatt (MW) = 1,000,000 watts (W)

What is the difference between kilowatt-Hours and kilowatts?

The comparison table given below highlighs the main differences between kilowatt-hours (kWh) and kilowatts (kW):

AspectKilowatt-Hours (kWh)Kilowatts (kW)
DefinitionA unit of energy, representing the total amount of electricity used or generated over a period of time.A unit of power, representing the rate at which electricity is consumed or produced at a specific moment.
MeasurementEnergy consumed or generated over time.Power consumption or production at a specific moment.
CalculationEnergy (kWh) = Power (kW) × Time (hours)N/A (Kilowatts do not depend on time.)
ExampleIf a device consumes 1 kW of power for 2 hours, it uses 2 kWh of energy.If a device has a power rating of 3 kW, it consumes 3 kW of power at any given moment.
BillingUsed for electricity bills to charge for actual energy consumed.Used for rating the capacity of electrical devices or systems.
RepresentationskWh is commonly used to represent household electricity consumption.kW is used to indicate the power capacity of appliances, generators, and electrical systems.
Units of Measure1 kWh = 1,000 watt-hours1 kW = 1,000 watts

How Do You Calculate the Energy Consumption of an Electrical Appliance?

To calculate the energy consumption of an electrical appliance, you need to know its power rating in watts and the amount of time it is used. The formula for calculating energy consumption is:

Energy (kWh) = Power (kW) × Time (hours)

Here’s a step-by-step guide to calculate the energy consumption:

  1. Find the Power Rating: Look for the power rating of the electrical appliance, usually indicated in watts (W) or kilowatts (kW). This information is typically found on a label or plate on the appliance itself. If it’s given in kilowatts, convert it to watts by multiplying by 1000 (1 kW = 1000 W).
  2. Determine the Time of Use: Decide the duration for which the appliance is being used. This can be in hours, minutes, or any time unit as long as you’re consistent with the power rating unit (e.g., if the power rating is in watts, use hours for time).
  3. Calculate Energy Consumption: Use the formula mentioned above to calculate the energy consumption in kilowatt-hours (kWh). Divide the power rating in watts by 1000 to convert it to kilowatts before multiplying it by the time in hours.
  4. Interpret the Result: The calculated value will represent the energy consumption of the appliance over the given time period. It indicates the total kilowatt-hours of energy consumed during that time.

For example, if you have a 100-watt light bulb (0.1 kW) and it’s used continuously for 5 hours, the energy consumption would be:

Energy (kWh) = 0.1 kW × 5 hours = 0.5 kWh

This means the light bulb consumed 0.5 kilowatt-hours of energy during the 5-hour period.

How Many Kilowatt-Hours Does the Average U.S. Household Use Per Day?

Based on the report of various energy agencies and studies, the average U.S. household consumes around 877 kilowatt-hours (kWh) of electricity per month. To find out the average daily usage, you can divide this value by the number of days in a month.

So, on average:

Average Daily Usage = 877 kWh / 30 days (approximately) ≈ 29.23 kWh per day

Please note that energy consumption can vary depending on factors such as the size of the household, climate, energy efficiency practices, and the use of energy-intensive appliances.

What’s the Difference Between Watts and Amps? 

The comparison table given below shows the main differences between watts and amps:

AspectWatts (W)Amps (A)
DefinitionA unit of power, representing the rate at which energy is consumed or produced.A unit of electric current, representing the rate of flow of electric charge in a circuit.
MeasurementPower consumption or production at a specific moment.Current flow at a specific moment.
FormulaPower (W) = Voltage (V) × Current (A)N/A (Amps are a primary unit and do not require a formula.)
ExampleA 60-watt light bulb consumes 60 watts of power when turned on.A circuit has a current of 5 amps, meaning 5 coulombs of charge flow through it every second.
Used inDescribes the capacity of electrical devices or systems, energy consumption, and production.Describes the current-carrying capacity of wires and components, safety ratings, and circuit design.
RelationshipPower (W) = Voltage (V) × Current (A)N/A (Amps are a primary unit and do not have a direct relationship with other units.)
Measured withPower meter or wattmeterAmmeter
Unit PrefixesKilowatt (kW), Megawatt (MW), etc.Milliampere (mA), Microampere (μA), etc.

Note: All the content on this page and the “Watts to kWh Calculator” are validated by Kenan BaltaciBethanie Stadler and Lee Roberts. They checked the algorithm, performance and accuracy of this calculator.