Energy Converter
Convert between joules, calories, kilowatt-hours, and more
Conversion Formula:
Multiply by 0.239006
Common Conversions
Energy Facts
- One kilowatt-hour (kWh) is enough energy to power a 100W lightbulb for 10 hours.
- The human body requires about 2000 kilocalories (food calories) per day, which is about 8.37 megajoules of energy.
- A single lightning strike contains approximately 5 billion joules, enough to power an average household for a month.
- One gram of uranium-235 can theoretically produce 83 terajoules of energy through nuclear fission.
- The Sun produces about 3.8 x 10^26 joules of energy every second.
Energy Equivalents
- 3.6 megajoules (MJ)
- 860 kilocalories (food calories)
- 3,412 British Thermal Units (BTU)
- 4.184 kilojoules (kJ)
- 0.00116 kilowatt-hours (kWh)
- 3.966 British Thermal Units (BTU)
- 1 gram of protein ≈ 4 kilocalories
- 1 gram of carbohydrates ≈ 4 kilocalories
- 1 gram of fat ≈ 9 kilocalories
History of Energy Units
The joule was named after English physicist James Prescott Joule, who contributed significantly to the field of thermodynamics in the 19th century.
The calorie was introduced by Nicolas Clément in 1824 as a unit of heat energy.
The British Thermal Unit (BTU) was defined in the late 19th century during the industrial revolution to measure the heat value of fuels.
The kilowatt-hour was first used in the early days of electrical power distribution in the 1890s and became standardized as electricity use spread.
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Visual Comparison
Energy Comparison
1000 j
1.00 kJ equivalent
Similar to: Energy in a single strawberry
A sweet but low-calorie fruit
239 cal
1.00 kJ equivalent
Similar to: Energy in a single strawberry
A sweet but low-calorie fruit
Energy Scale
This logarithmic scale shows where these energy values fall in the universal energy spectrum
Marker A: 1000 j
1.00 kJ
Marker B: 239 cal
1.00 kJ
Common Energy Equivalents
Mobile tip: Swipe left or right on the unit dropdown to quickly change units, or use the arrow buttons
About the Energy Converter
Convert between joules, calories, kilowatt-hours, and more All conversions run instantly in your browser and nothing you enter is sent to a server.
Common Conversion Formulas
| From | To | Formula |
|---|---|---|
| Joules (J) | Calories (cal) | cal = J × 0.239006 |
| Kilowatt-hours (kWh) | Megajoules (MJ) | MJ = kWh × 3.6 |
| British thermal units (BTU) | Joules (J) | J = BTU × 1055.06 |
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