Energy Converter
Convert energy between joules, calories, kilocalories, BTU, kilowatt-hours, and 39+ units. Essential for nutrition labeling, physics, electrical engineering, and heating calculations. See also our kJ to kcal and Joules to Calories converters.
Value:
Popular Energy Converters:
What is a Energy Converter?
An energy converter is a tool that converts measurements between different units of energy such as joules, calories, kilocalories, BTU, and kilowatt-hours. It is used in physics, nutrition, engineering, and utility billing where energy values need to be compared across different systems.
How to Convert Energy Units
Select the energy unit you want to convert from and the unit you want to convert to using the dropdown menus. Enter your value in the input field and the converter will instantly calculate the equivalent energy. Use the popular conversion links below for common conversions like kJ to kcal.
Energy Conversion Formulas
History of Energy Measurement
James Prescott Joule established the mechanical equivalent of heat in the 1840s, leading to the joule becoming the SI unit of energy. The calorie was defined by Nicolas Clement in 1824 as a unit of heat. The kilowatt-hour became standard for electrical billing in the late 19th century as electricity distribution expanded.
About This Energy Converter
This energy converter supports 39 different units including joule, kilojoule, megajoule, calorie (IT and thermochemical), kilocalorie, BTU, kilowatt-hour, electron-volt, erg, foot-pound, therm, watt-hour, and more. It serves scientists, engineers, nutritionists, and students.
Frequently Asked Questions
How do I convert calories to joules?
Multiply calories by 4.1868 to get joules. For example, 100 calories = 100 × 4.1868 = 418.68 joules. Note: food "Calories" (capital C) are actually kilocalories.
What is the difference between a calorie and a kilocalorie?
A kilocalorie (kcal) equals 1,000 calories. Food labels use "Calories" (capital C) which are actually kilocalories. So 2,000 food Calories = 2,000 kcal = 2,000,000 cal.
How do I convert kWh to joules?
Multiply kilowatt-hours by 3,600,000 to get joules. For example, 1 kWh = 3.6 million joules. This is because 1 kWh = 1,000 watts × 3,600 seconds.
How many BTU are in a kilowatt-hour?
One kilowatt-hour equals approximately 3,412.14 BTU. This conversion is commonly used in HVAC and energy efficiency calculations.
What is an electron-volt?
An electron-volt (eV) is the energy gained by an electron moving through 1 volt of potential difference. It equals 1.602 × 10⁻¹⁹ joules and is used in particle physics and quantum mechanics.
Metric Conversion Factor Tables for Energy Converter
| Units to convert | Multiply By The Number | Convert as Unit |
|---|---|---|
| Joule (J) | 0.001 | Kilojoule (kJ) |
| Joule (J) | 0.2388458966 | Calorie (cal) (IT) |
| Joule (J) | 0.0009478171 | BTU (IT) |
| Kilojoule (kJ) | 1000 | Joule (J) |
| Kilojoule (kJ) | 0.2388458966 | Kilocalorie (kcal) |
| Kilocalorie (kcal) | 4.1868 | Kilojoule (kJ) |
| Kilocalorie (kcal) | 1000 | Calorie (cal) |
| Kilocalorie (kcal) | 3.9683207 | BTU (IT) |
| Calorie (cal) | 4.1868 | Joule (J) |
| Calorie (cal) | 0.001 | Kilocalorie (kcal) |
| BTU (IT) | 1055.056 | Joule (J) |
| BTU (IT) | 1.055056 | Kilojoule (kJ) |
| Kilowatt-hour (kWh) | 3600000 | Joule (J) |
| Kilowatt-hour (kWh) | 3412.1416 | BTU (IT) |
| Foot-pound (ft*lbf) | 1.3558179 | Joule (J) |
| Foot-pound (ft*lbf) | 0.001285067 | BTU (IT) |
| Electron-volt (eV) | 1.60218e-19 | Joule (J) |
| Erg | 1e-7 | Joule (J) |
| Therm | 100000 | BTU (IT) |
Energyconverters & it's abbreviations
| Unit | Abbreviation | Unit | Abbreviation | Unit | Abbreviation |
|---|---|---|---|---|---|
| joule | J | kilojoule | kJ | megajoule | MJ |
| gigajoule | GJ | calorie (IT) | cal | calorie (th) | cal |
| kilocalorie (IT) | kcal | kilocalorie (th) | kcal | calorie (nutritional) | Cal |
| BTU (IT) | Btu | BTU (th) | Btu | kilowatt-hour | kWh |
| watt-hour | Wh | watt-second | Ws | electron-volt | eV |
| megaelectron-volt | MeV | erg | erg | foot-pound | ft·lbf |
| newton meter | N·m | therm | thm | ton (explosives) | ton |
| kiloton | kton | microjoule | µJ | millijoule | mJ |
| nanojoule | nJ | megawatt-hour | MWh | gigawatt-hour | GWh |
| Hartree energy | Eh | Rydberg constant | Ry |
Complete list of Energy conversion units and its conversion.
- 1 joule [J] = 0.001 kilojoule [kJ]
J to kJ → - 1 joule [J] = 0.2388458966 calorie (IT) [cal]
joules to calories → - 1 joule [J] = 0.0009478171 BTU (IT)
joules to BTU →
- 1 kilojoule [kJ] = 0.2388458966 kilocalorie (IT) [kcal]
kJ to kcal → - 1 kilojoule [kJ] = 0.9478171203 BTU (IT)
kJ to BTU → - 1 kilojoule [kJ] = 0.0002777778 kilowatt-hour [kWh]
kJ to kWh →
- 1 kilocalorie (IT) [kcal] = 3.9683207 BTU (IT)
kcal to BTU → - 1 calorie (IT) [cal] = 4.1868 joule [J]
calories to joules → - 1 calorie (IT) [cal] = 0.001 kilocalorie [kcal]
cal to kcal →
- 1 BTU (IT) = 0.2520 kilocalorie [kcal]
BTU to kcal → - 1 BTU (IT) = 252.0 calorie [cal]
BTU to calories → - 1 kilowatt-hour [kWh] = 3600000 joule [J]
kWh to joules →
- 1 foot-pound [ft*lbf] = 1.3558179483 joule [J]
ft-lb to joules → - 1 foot-pound [ft*lbf] = 1.3558179 newton meter [N.m]
ft-lb to Nm → - 1 newton meter [N.m] = 0.7375621493 foot-pound [ft*lbf]
Nm to ft-lb →
- 1 watt-hour [Wh] = 3600 joule [J]
Wh to J → - 1 watt-hour [Wh] = 3.6 kilojoule [kJ]
Wh to kJ → - 1 therm = 100000 BTU (IT)
therm to BTU →
- 1 joule [J] = 0.000001 megajoule [MJ]
J to MJ → - 1 joule [J] = 0.7375621493 foot-pound [ft*lbf]
joules to ft-lb → - 1 kilojoule [kJ] = 1000 joule [J]
kJ to J →
- 1 kilocalorie (IT) [kcal] = 4.1868 kilojoule [kJ]
kcal to kJ → - 1 kilocalorie (IT) [kcal] = 1000 calorie (IT) [cal]
kcal to cal → - 1 kilocalorie (IT) [kcal] = 4186.8 joule [J]
kcal to joules →
- 1 calorie (IT) [cal] = 0.003968321 BTU (IT)
cal to BTU → - 1 BTU (IT) = 1055.05585262 joule [J]
BTU to joules → - 1 BTU (IT) = 1.05505585 kilojoule [kJ]
BTU to kJ →
- 1 kilowatt-hour [kWh] = 3600 kilojoule [kJ]
kWh to kJ → - 1 kilowatt-hour [kWh] = 3412.1416 BTU (IT)
kWh to BTU → - 1 kilowatt-hour [kWh] = 859845.2279 calorie [cal]
kWh to calories →
- 1 megajoule [MJ] = 1000 kilojoule [kJ]
MJ to kJ → - 1 megajoule [MJ] = 1000000 joule [J]
MJ to J → - 1 megajoule [MJ] = 0.2777778 kilowatt-hour [kWh]
MJ to kWh →
- 1 therm = 105505585.262 joule [J]
therm to joules → - 1 erg = 1e-7 joule [J]
erg to joules → - 1 electron-volt [eV] = 1.60218e-19 joule [J]
eV to joules →