How many kJ are in a kWh?

3,600 kilojoules make 1 kilowatt hour. Multiples follow directly: 2 kWh is 7,200 kJ and 0.5 kWh is 1,800 kJ. Press the swap button between the boxes to run the page that way round, with Kilowatt hour in the From box and Kilojoule in the To box.

What is the formula for kJ to kWh?

kWh = kJ / 3,600, and kJ = kWh x 3,600 in reverse. The 3,600 is not a measured constant: a watt is defined as a joule per second, an hour is 3,600 seconds, so a watt hour is 3,600 joules and a kilowatt hour is 3,600 kilojoules. That makes this conversion exact by definition rather than an approximation, however long the decimal turns out.

Worked example: how many kWh is 10,000 kJ?

2.77777777778 kWh. Type 10,000 into the From box, with or without the commas, and 1e4 is read the same way. The list underneath restates it in the rest of the category, and at 100 kJ those rows read 100,000 J, 27.7777777778 Wh, 23,900.5736138 cal, 23.9005736138 kcal and 94.7817120313 BTU. Each row has its own Copy button, and Copy result above the list copies the headline without its thousands separators.

Why is the answer a repeating decimal?

Because 1 divided by 3,600 does not terminate in base ten. One kilojoule is 0.000277777777778 kWh as the page prints it, with the sevens running to the 12 significant digits it keeps, and 1,000 kJ is 0.277777777778 kWh. The direction that does land clean is the other one, since any whole number of kilowatt hours is a whole number of kilojoules, and any multiple of 360 kJ is a clean answer too: 360 kJ is 0.1 kWh.

How do kilojoules relate to watt hours?

3.6 kJ is 1 Wh, so a kilojoule is 0.277777777778 Wh and 3,600 kJ is 1,000 Wh. The watt hour row sits in the list under the headline on every conversion, which is often the more readable unit for a battery or a small appliance figure, where a kilowatt hour answer would be a string of zeros after the point.

Which calorie and which BTU does the list use?

The calorie here is the thermochemical calorie of exactly 4.184 joules, and the kilocalorie is 1,000 of those, so 1 kJ is 239.005736138 cal and 0.239005736138 kcal. The International Table calorie of 4.1868 J is a different definition and is not in this table, so a source using it will differ in the fourth digit. The BTU row is the International Table BTU of 1,055.05585262 J, which makes 1 kJ 0.947817120313 BTU and 1,000 kJ 947.817120313 BTU.

What is the electronvolt row for?

Switch on Show 1 more and the electronvolt joins the list, where 1 kJ is 6.241509e21 eV. It prints in exponential notation because the page moves to exponents above 1e15, which keeps a 22-digit figure from running off the line. It is there for physics arithmetic rather than for anything a meter reads.

Does converting kJ to kWh account for efficiency?

No. A kilojoule and a kilowatt hour are two names for the same amount of energy, and this page only changes the name. How much of that energy a motor, a heater or a charger actually delivers as useful work is a property of the machine, not of the units, so a conversion here is the input to that question rather than the answer to it.

kJ to kWh Converter

A kilojoule and a kilowatt hour measure the same thing at very different scales: a watt is one joule per second, an hour is 3,600 seconds, and the kilo on each side cancels, so 3,600 kJ is exactly 1 kWh. This page opens with Kilojoule in the From box and Kilowatt hour in the To box, ahead of whatever pair the converter last remembered, so 100 kJ reads 0.0277777777778 kWh, 1,800 kJ reads 0.5 kWh and 36,000 kJ reads 10 kWh. Because 1/3,600 never terminates as a decimal, a single kilojoule prints as 0.000277777777778 kWh at the 12 significant digits the page carries, while the same conversion read backwards is exact. Under the headline the same energy appears in joules, watt hours, calories, kilocalories and BTU at once, with the electronvolt held behind a Show 1 more switch, and the swap button turns the page into a kilowatt hours to kilojoules converter.

From

To0.000277777777778

1 kJ in every energy unit

JouleJ
1,000
Caloriecal
239.005736138
Kilocaloriekcal
0.239005736138
Watt hourWh
0.277777777778
Kilowatt hourkWh
0.000277777777778
British thermal unitBTU
0.947817120313

Common questions

How many kJ are in a kWh?: 3,600 kilojoules make 1 kilowatt hour. Multiples follow directly: 2 kWh is 7,200 kJ and 0.5 kWh is 1,800 kJ. Press the swap button between the boxes to run the page that way round, with Kilowatt hour in the From box and Kilojoule in the To box.
What is the formula for kJ to kWh?: kWh = kJ / 3,600, and kJ = kWh x 3,600 in reverse. The 3,600 is not a measured constant: a watt is defined as a joule per second, an hour is 3,600 seconds, so a watt hour is 3,600 joules and a kilowatt hour is 3,600 kilojoules. That makes this conversion exact by definition rather than an approximation, however long the decimal turns out.
Worked example: how many kWh is 10,000 kJ?: 2.77777777778 kWh. Type 10,000 into the From box, with or without the commas, and 1e4 is read the same way. The list underneath restates it in the rest of the category, and at 100 kJ those rows read 100,000 J, 27.7777777778 Wh, 23,900.5736138 cal, 23.9005736138 kcal and 94.7817120313 BTU. Each row has its own Copy button, and Copy result above the list copies the headline without its thousands separators.
Why is the answer a repeating decimal?: Because 1 divided by 3,600 does not terminate in base ten. One kilojoule is 0.000277777777778 kWh as the page prints it, with the sevens running to the 12 significant digits it keeps, and 1,000 kJ is 0.277777777778 kWh. The direction that does land clean is the other one, since any whole number of kilowatt hours is a whole number of kilojoules, and any multiple of 360 kJ is a clean answer too: 360 kJ is 0.1 kWh.
How do kilojoules relate to watt hours?: 3.6 kJ is 1 Wh, so a kilojoule is 0.277777777778 Wh and 3,600 kJ is 1,000 Wh. The watt hour row sits in the list under the headline on every conversion, which is often the more readable unit for a battery or a small appliance figure, where a kilowatt hour answer would be a string of zeros after the point.
Which calorie and which BTU does the list use?: The calorie here is the thermochemical calorie of exactly 4.184 joules, and the kilocalorie is 1,000 of those, so 1 kJ is 239.005736138 cal and 0.239005736138 kcal. The International Table calorie of 4.1868 J is a different definition and is not in this table, so a source using it will differ in the fourth digit. The BTU row is the International Table BTU of 1,055.05585262 J, which makes 1 kJ 0.947817120313 BTU and 1,000 kJ 947.817120313 BTU.
What is the electronvolt row for?: Switch on Show 1 more and the electronvolt joins the list, where 1 kJ is 6.241509e21 eV. It prints in exponential notation because the page moves to exponents above 1e15, which keeps a 22-digit figure from running off the line. It is there for physics arithmetic rather than for anything a meter reads.
Does converting kJ to kWh account for efficiency?: No. A kilojoule and a kilowatt hour are two names for the same amount of energy, and this page only changes the name. How much of that energy a motor, a heater or a charger actually delivers as useful work is a property of the machine, not of the units, so a conversion here is the input to that question rather than the answer to it.

Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.