OneTaskBy Tim King · Updated
Joules to kWh and kWh to Joules Converter
Joules to Kilowatt-Hours, Divide by 3.6 Million, Both Directions
kilowatt-hours to joules table ↓
joules to kilowatt-hours formula
kWh = J ÷ 3,600,000
1 joule = 0.0000002778 kilowatt-hours, so multiply joules by 0.0000002778. Going the other way, 1 kilowatt-hour = 3,600,000 joules.
joules to kilowatt-hours table
| joules (J) | kilowatt-hours (kWh) |
|---|---|
| 1,000 | 0.000277778 |
| 3,600 | 0.001 |
| 10,000 | 0.00277778 |
| 50,000 | 0.0138889 |
| 100,000 | 0.0277778 |
| 360,000 | 0.1 |
| 500,000 | 0.138889 |
| 1,000,000 | 0.277778 |
| 1,800,000 | 0.5 |
| 3,600,000 | 1 |
| 5,000,000 | 1.38889 |
| 10,000,000 | 2.77778 |
| 18,000,000 | 5 |
| 36,000,000 | 10 |
| 50,000,000 | 13.8889 |
| 100,000,000 | 27.7778 |
| 216,000,000 | 60 |
| 360,000,000 | 100 |
| 500,000,000 | 138.889 |
| 1,000,000,000 | 277.778 |
| 3,600,000,000 | 1,000 |
| 10,000,000,000 | 2,777.78 |
| 36,000,000,000 | 10,000 |
| 100,000,000,000 | 27,777.8 |
How many kilowatt-hours in joules?
3,600 J = 0.001 kWh. There are 0.001 kilowatt-hours in 3,600 joules.
1,000,000 J = 0.277778 kWh. There are 0.277778 kilowatt-hours in 1,000,000 joules.
3,600,000 J = 1 kWh. There are 1 kilowatt-hours in 3,600,000 joules.
1,000,000,000 J = 277.778 kWh. There are 277.778 kilowatt-hours in 1,000,000,000 joules.
36,000,000,000 J = 10,000 kWh. There are 10,000 kilowatt-hours in 36,000,000,000 joules.
kilowatt-hours to joules formula
J = kWh × 3,600,000
1 kilowatt-hour = 3,600,000 joules, so multiply kilowatt-hours by 3,600,000, or divide by 0.0000002778.
kilowatt-hours to joules table
| kilowatt-hours (kWh) | joules (J) |
|---|---|
| 0.001 | 3,600 |
| 0.01 | 36,000 |
| 0.05 | 180,000 |
| 0.1 | 360,000 |
| 0.25 | 900,000 |
| 0.5 | 1,800,000 |
| 1 | 3,600,000 |
| 1.5 | 5,400,000 |
| 2 | 7,200,000 |
| 2.5 | 9,000,000 |
| 3 | 10,800,000 |
| 5 | 18,000,000 |
| 7.5 | 27,000,000 |
| 10 | 36,000,000 |
| 15 | 54,000,000 |
| 20 | 72,000,000 |
| 25 | 90,000,000 |
| 30 | 108,000,000 |
| 50 | 180,000,000 |
| 60 | 216,000,000 |
| 75 | 270,000,000 |
| 100 | 360,000,000 |
| 250 | 900,000,000 |
| 500 | 1,800,000,000 |
| 1,000 | 3,600,000,000 |
| 2,700 | 9,719,999,999 |
| 5,000 | 17,999,999,999 |
| 10,000 | 35,999,999,997 |
How many joules in kilowatt-hours?
1 kWh = 3,600,000 J. There are 3,600,000 joules in 1 kilowatt-hours.
2 kWh = 7,200,000 J. There are 7,200,000 joules in 2 kilowatt-hours.
10 kWh = 36,000,000 J. There are 36,000,000 joules in 10 kilowatt-hours.
60 kWh = 216,000,000 J. There are 216,000,000 joules in 60 kilowatt-hours.
100 kWh = 360,000,000 J. There are 360,000,000 joules in 100 kilowatt-hours.
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How the Joules To KWh works
This joules to kWh converter shows where the factor comes from. Type an energy in joules and get kilowatt-hours as you type. A kilowatt-hour is 1,000 W for 3,600 s, which is 3,600,000 J, so divide by 3.6 million. The table is in joules but the useful landmarks are 3.6 kJ for a watt-hour, 3.6 MJ for a kilowatt-hour and 3.6 GJ for a megawatt-hour. Press the swap button to go the other way.
Joules to kWh: where the factor comes from
A joule is a watt-second. A kilowatt-hour is 1,000 watts for 3,600 seconds, so 1 kWh = 3,600,000 J and 1 J = 0.000000277778 kWh. The prefixes line up: 3.6 kJ is a Wh, 3.6 MJ is a kWh, 3.6 GJ is an MWh. The number is exact, and the conversion is only ever a matter of dividing by 3.6 and moving the decimal point.
Worked example: a physics answer of 216,000,000 J
216,000,000 ÷ 3,600,000 = 60 kWh. A question that computes the energy in a car battery, or the work done by a motor, comes out in joules; the datasheet figure is in kilowatt-hours. Going from a 10 kg mass lifted 100 m: 10 × 9.81 × 100 = 9,810 J, which is 0.0027 kWh — a fraction of a penny of electricity, which is why lifting things is cheap and heating them is not.
Worked example: heating water
Heating 1 litre of water from 20 °C to 100 °C takes 1,000 g × 4.184 J/g°C × 80 = 334,720 J, or 0.093 kWh. A 3 kW kettle does it in 112 seconds at 100% efficiency and about two minutes in practice. A 150-litre hot water tank from 10 °C to 60 °C is 31.4 MJ, 8.7 kWh.
Batteries and appliances
Battery capacity in joules is rare, but a supercapacitor's ½CV² is in joules: a 3,000 F capacitor at 2.7 V holds 10,935 J, or 0.003 kWh, a thousandth of a phone charge. A microwave at 900 W for 2 minutes uses 108,000 J, 0.03 kWh. An LED bulb at 10 W for a day uses 864,000 J, 0.24 kWh.
Megajoules and gigajoules
Gas is billed in megajoules in Australia and gigajoules in Canada. 1 MJ is 0.2778 kWh, 1 GJ is 277.8 kWh. A typical Australian household's 20,000 MJ of gas a year is 5,556 kWh.
Rule of thumb
Divide joules by 3.6 and knock off six zeros. 7,200,000 J is 2 kWh. 1 MJ is a bit more than a quarter of a kWh.
Worked example: a 2,700 kWh year
2,700 × 3,600,000 = 9.72 × 10⁹ J, or 9.72 GJ. The average British household uses about 2,700 kWh of electricity a year, and gas bills are also in kWh: 11,500 kWh of gas is 41.4 GJ. Gas meters record cubic metres and the bill converts them using a calorific value of about 39.5 MJ/m³, 10.97 kWh/m³.
Worked example: a 60 kWh car battery
60 × 3,600,000 = 216 MJ. A litre of petrol holds about 34 MJ, so the battery stores the energy of 6.4 litres, and it takes a car 300 km because the motor is three to four times as efficient as an engine. A phone battery at 15 Wh is 54 kJ; a laptop at 60 Wh is 216 kJ; a power bank at 20,000 mAh × 3.7 V is 74 Wh, 266 kJ.
Joule to kilowatt-hours formula and table
The formula on this page is kWh = J ÷ 3,600,000, applied exactly before rounding for display.
How many kilowatt-hours in 3,600 joules? 3,600 J is 0.001 kWh. Likewise 1,000,000 J is 0.2778 kWh, 3,600,000 J is 1 kWh, 1,000,000,000 J is 277.78 kWh.
Joule to kilowatt-hour conversion table
| Joules (J) | Kilowatt-hours (kWh) |
|---|---|
| 1,000 | 0.00027778 |
| 3,600 | 0.001 |
| 10,000 | 0.00277778 |
| 50,000 | 0.0139 |
| 100,000 | 0.0278 |
| 360,000 | 0.1 |
| 500,000 | 0.1389 |
| 1,000,000 | 0.2778 |
| 1,800,000 | 0.5 |
| 3,600,000 | 1 |
| 5,000,000 | 1.3889 |
| 10,000,000 | 2.7778 |
| 18,000,000 | 5 |
| 36,000,000 | 10 |
| 50,000,000 | 13.89 |
| 100,000,000 | 27.78 |
| 216,000,000 | 60 |
| 360,000,000 | 100 |
| 500,000,000 | 138.89 |
| 1,000,000,000 | 277.78 |
| 3,600,000,000 | 1,000 |
| 10,000,000,000 | 2,778 |
| 36,000,000,000 | 10,000 |
| 100,000,000,000 | 27,778 |
FAQ
How many kWh are in a joule?
0.000000277778 kWh, or 2.78 × 10⁻⁷. The joule is tiny compared with the kilowatt-hour: it takes 3.6 million of them. A megajoule is 0.2778 kWh.
How many kWh is 1 MJ?
0.2778 kWh, or five-eighteenths. A litre of petrol at 34 MJ is 9.4 kWh; a cubic metre of natural gas at about 39.5 MJ is 10.97 kWh, the figure on a gas bill.
How do I convert joules to kWh for a physics question?
Divide by 3,600,000. Energy from a formula — work, kinetic energy, heat — is in joules if the inputs are SI. If the answer needs to be compared with an electricity bill, divide by 3.6 million.
What is a gigajoule in kWh?
277.78 kWh. Gigajoules appear on Canadian gas bills and in energy statistics; a gigajoule of gas is about 26 cubic metres, and a household might use 100 GJ a year, 27,778 kWh.
How many joules are in a kilowatt-hour?
3,600,000 joules, exactly. A watt is a joule per second, a kilowatt is 1,000 of those, and an hour is 3,600 seconds. So 1 kWh is 3.6 MJ.
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