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Watt Hour Calculator

Watt Hour Calculator

Enter the required values to calculate the amount of energy consumed in watt hours over some time.




Watt-hours from time




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This watt hour calculator lets you determine how much energy a device is consuming in watt hours for understanding and managing the power consumption.

This tool helps to estimate electricity usage and assess the energy efficiency of different devices and appliances. By using it, you can easily convert the amp hours or milliamp hours to watt-hours.

What Is Watt Hour?

“The total amount of energy consumed by a device or an appliance over a specific time”

Watt hour is the unit of energy which is equal to 3,600 joules. It shows how many watts are used in one hour by a specific device or appliance. It is used to calculate energy in watt-hours.

How To Calculate Watt Hours?

To calculate watt-hours, use the following formula:

Wh = Ah × V


  • Wh is the watt hours
  • Ah represents the amp hour
  • V is the voltage

Keep in mind that one amp hour is equal to 1000 milliamp hours so to convert amp to milliamp divide the value of mAh by 1000.


Let’s assume you have a rechargeable battery with a capacity of 2500 milliamp-hours (mAh) and a voltage of 3.7 volts. Find the energy capacity of the battery in watt-hours.


Given that:

Battery Capacity = Charge = 2500 mAh = 2500/1000 = 2.5 Ah

Voltage = 3.7 volts

Now put the given values in the watt hour formula for calculating watt hours:

Wh = Ah × V

Watt-hours (Wh) = 2.5 Ah × 3.7 V = 9.25 Wh

If you want to convert the results into kilowatt-hours, then divide it by 1000.

Watt-hours = 9.25 Wh/1000 = 0.00925 K

If you want to perform seamless conversion from watt-hours to amp-hours, try the amp hour calculator.

How To Calculate Watt Hours From Time?

To calculate watt hours over some time t in hours, the formula is as follows:

Wh = W × t


  • Wh is the watt
  • V is the voltage


Let’s say you have an appliance with a power consumption of 30 watts, find out how many watt-hours it consumes if it runs for 3 hours.


Given that:

Power Consumption = W = 30 watts

Time = t = 3 hours

Put values in the watt-hour formula:

Watt-hours (Wh) = 30 W×3 h

Watt-hours (Wh) = 90 Wh

The device will consume 150 watt-hours of energy over 3 hours.

Instead of wasting your time on manual calculation, use the watt-hour calculator and get precise results in seconds.

Importance of Watt-Hours:

Watt-hours are important for many reasons, including:

  • Help to assess the battery capacity, Therefore, people who have battery-powered devices or renewable energy systems may use the watt hour calculator to assess battery capacity requirements instantly
  • Watt hours let you determine the energy usage of electrical devices or appliances
  • Allow you to cut energy consumption and electricity bills

For more information, visit the source

Difference Between Watts And Watt-Hours:

Watt and watts-hour are connected but they capture different aspects of electrical power. Here, we have outlined the difference between watts and watt-hours:

  • Watts is a unit of power, whereas watt-hours is a unit of energy
  • Watts define the power of a device or an appliance while the watt-hours are the consumption of power over a specific period
  • Watts indicate the amount of energy a device or appliance needs to function properly whereas watt hours show the energy consumed by the device or appliance in a specific time


How Do You Convert Wh To Watts?

To convert watt-hours to watts, divide the energy (E) in watt-hours by the time (t) in hours (h).

\(\ Energy\ (E) =\ Power\ (Wh)\times \ Time\ (t)\)

Rearrange the equation:

\(\ Power =\dfrac{Energy\ (E)}{Time\ (t)}\)

By using this equation, you will have power in watts.

What Is 1 Watt-Hour?

The One watt-hour (Wh) is a unit for the measurement of the energy. It is equal to the consumption of one watt of power for one hour.

1 Wh = 1 W × 1 h

Why Do We Convert Amp Hours To Watt-Hours?

The conversion to watt-hours allows you to understand the actual energy consumed by a device or an appliance. It helps compare batteries and to estimate how much energy can be stored in a battery.