kWh · J · kcal · BTU
Energy converter
One kilowatt-hour is exactly 3.6 megajoules, or 3412.14 BTU, or 860.421 kilocalories. Enter an energy, pick a unit and read it in all ten units at once.
- 1 kWh = 3.6 MJ
- 1 kJ = 0.2390057 kcal
The result and the table below it update as you type. Only the printed figure is rounded, to six significant digits, so a rounded value is never carried into the next conversion.
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- Units
- Joule, kilojoule, megajoule, watt-hour, kilowatt-hour, calorie, kilocalorie, BTU, foot-pound-force and electronvolt
- Definitions
- Thermochemical calorie 4.184 J, International Table BTU 1055.05585262 J
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- Any modern browser
Common energy conversions
These tables are computed from the same factors as the converter. Read each one left to right: the first column is the value you start with and the second is its equivalent.
| kWh | MJ |
|---|---|
| 1 | 3.6 |
| 10 | 36 |
| 100 | 360 |
| 500 | 1800 |
| 1000 | 3600 |
| kJ | kcal |
|---|---|
| 1 | 0.239006 |
| 10 | 2.39006 |
| 100 | 23.9006 |
| 500 | 119.503 |
| 1000 | 239.006 |
| kcal | kJ |
|---|---|
| 1 | 4.184 |
| 10 | 41.84 |
| 100 | 418.4 |
| 500 | 2092 |
| 1000 | 4184 |
| kWh | BTU |
|---|---|
| 1 | 3412.14 |
| 10 | 34121.4 |
| 100 | 341214 |
| 500 | 1706070 |
| 1000 | 3412140 |
| BTU | kJ |
|---|---|
| 1 | 1.05506 |
| 10 | 10.5506 |
| 100 | 105.506 |
| 500 | 527.528 |
| 1000 | 1055.06 |
| Wh | J |
|---|---|
| 1 | 3600 |
| 10 | 36000 |
| 100 | 360000 |
| 500 | 1800000 |
| 1000 | 3600000 |
Energy units and their exact size
| Unit | Symbol | Exact size |
|---|---|---|
| Joule | J | 1 J = 1 J |
| Kilojoule | kJ | 1 kJ = 1000 J |
| Megajoule | MJ | 1 MJ = 1000000 J |
| Watt-hour | Wh | 1 Wh = 3600 J |
| Kilowatt-hour | kWh | 1 kWh = 3600000 J |
| Calorie (thermochemical) | cal | 1 cal = 4.184 J |
| Kilocalorie (food Calorie) | kcal | 1 kcal = 4184 J |
| BTU (International Table) | BTU | 1 BTU = 1055.05585262 J |
| Foot-pound-force | ft·lbf | 1 ft·lbf = 1.3558179483314 J |
| Electronvolt | eV | 1 eV = 1.602176634e-19 J |
How to convert an energy
Enter the energy
Type a number in the first field. Negative values and decimals are accepted, so 2000 and 0.5 both work.
Pick the two units
Choose the unit you have in the first menu and the unit you want in the second. The swap button reverses the two.
Read the table
The large figure is your answer. The table lists the same energy in every other unit, so you can copy the one you need without converting again.
How energy conversion works
Every unit on this page is defined from the joule, which is one newton metre or one watt-second. A watt-hour is 3600 J and a kilowatt-hour is 3600000 J. The calorie is the one that varies: this page uses the thermochemical calorie, exactly 4.184 J, and the kilocalorie of 4184 J, which is the food Calorie printed on nutrition labels. The International Table BTU is exactly 1055.05585262 J, and the foot-pound-force is 1.3558179483314 J.
A conversion is a multiplication and a division: the value times the source unit's size in joules, divided by the target unit's. Kilowatt-hours to kilocalories is value × 3600000 ÷ 4184, which is value × 860.421 to six digits. The electronvolt is exactly 1.602176634e-19 J since the 2019 redefinition of the SI. Other calories exist, such as the International Table calorie of 4.1868 J, and they differ from the thermochemical one by about 0.07 percent, which this page does not offer.
Energy conversion questions
How many joules are in a kilowatt-hour?
One kilowatt-hour is exactly 3600000 joules, or 3.6 MJ, because a kilowatt is 1000 joules per second and an hour is 3600 seconds. It is also 1000 Wh and 3412.14 BTU.
How many kilojoules are in a food Calorie?
One food Calorie, written kcal, is 4.184 kJ. A 2000 kcal day is 8368 kJ, which is 2.32444 kWh. One thermochemical calorie in lowercase is 4.184 J.
How many BTU are in a kWh?
One kWh is 3412.14 BTU, using the International Table BTU of 1055.05585262 J. Ten kWh is 34121.4 BTU. Going the other way, one BTU is 1.05506 kJ.
How many kilocalories are in a kilowatt-hour?
One kWh is 860.421 kcal, found by dividing 3600000 J by 4184 J. Divide kcal by 860.421 to get kWh.
Do my numbers leave my device?
No. The unit tables are part of the page and the arithmetic runs in your browser, so nothing you type is sent anywhere. With the page already loaded, the converter also works offline.