Kilowatts to kilowatt-hours calculator (kW to kWh)

Kilowatts to kilowatt-hours calculator (kW to kWh)

Electrical appliances have a power rating given in watts or kilowatts that indicates the amount of electricity the device requires to run and provide the necessary output.

The appliance manufacturer labels the power rating during the packaging of the equipment.

It is very vital for a consumer when purchasing the appliance as the consumer can estimate the energy supply required and the cost of the energy to use.

Kilowatts and kilowatt-hour

Watt is the standard unit of electrical power. Kilowatts (kW) is equivalent to 1000 watts. Kilowatt-hours (kWh) is the electricity demand for an appliance to run over a given period.

Kilowatt-hour is the basic unit for energy bills as it’s used to calculate the energy costs and a way to quantify the amount of energy used.

Convert kilowatts to kilowatt-hour

Kilowatts to kilowatt-hours is a significant conversion in electricity billing as it reflects the rate of electricity used and the total amount of energy used.

The conversion involves watts to kilowatts and kilowatts to kilowatts-hour. To convert watts to kilowatts, divide the watts by 1000 to get the kilowatts.

Kilowatts to kilowatt-hour conversion can apply the formula:

Energy (E) is equal to electrical power (P) times time (T) in hours.

E = P*T

E = energy defined by the amount of electricity used (kWh).

P = Power defined as the rating for an appliance (kW).

T = Time (hours)

It is important to note that the power rating should be in kilowatts (kW), and time should be in hours (h).


For the calculation of kWh, all you need to have and the note is the power and the number of hours of consumption. For instance, taking an appliance X rated at 3kW that is used for 4 hours, the energy consumed (kWh) is 12kWh. The calculation is as follows;

1) Formula: E (kWh)= P(kW)*T(h)

2) Values given: P = 3kW and T = 4h

3) E = 3kW*4h

E = 12kWh

In the case the appliance X is used for 15 minutes, the energy calculation is as follows;

1) Formula: E (kWh)= P(kW)*T(h)

2) T = 15 minutes

Convert the minutes into hours. Divide the 15 minutes by 60.

15/60 = 0.25hrs

P = 3kW

3) E = 3kW*0.25h

E = 0.75kWh

In the case of an appliance rated at 50 watts and used for 1 hour the energy consumption (kWh) calculation is;

1) Formula: E (kWh)= P(kW)*T(h)

2) P = 50 watts

Convert the watts into kilowatts. Divide the 50 watts by 1000 to get 0.05kW

50W/1000 = 0.05kW

3) E = 0.05kW*1h

E = 0.05kWh

The consumer will estimate the cost of energy an appliance will consume even before buying any appliance by considering the power rating provided for the appliance and applying the above formula.

Kilowatts to kilowatt-hours calculator (kW to kWh)

To successfully implement the formula in the calculator, the consumer or the buyer of the appliance should note the elements of the formula and their units and do any necessary conversion to fit the formula.

Getting versed in these conversions will help you at some time in your life.

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