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Conversions of many more energy units
1 Joule = 0.239005736 calories (thermo-chemical)
1 Joule = 0.0002388 calories (nutritional)
Energy and work conversion chart
Sorted from less to more
| Name Energy, work, or heat of unit, E | Symbol | Definition | Relation to SI unit joule, J |
| joule (SI unit) | J | ≡ N·m = W·s = V·A·s | = kg·m²/s² |
| electronvolt | eV | ≡ e × 1 V | ≈ 1.602 176×10−19J |
| rydberg | Ry | ≡ R∞·h·c | ≈ 2.179 872×10−18 J |
| hartree | Eh | ≡ me·α²·c²(= 2 Ry) | ≈ 4.359 744×10−18 J |
| atomicunit of energy | au | ≡ Eh ≈ 4.359 744×10−18 J | |
| erg (cgs unit) | erg | ≡ 1 g·cm²/s² | = 10−7 J |
| foot-poundal | ft pdl | ≡ 1 lb·ft²/s² | = 4.214 011 009 380 48×10−2 J |
| cubiccentimetre of atmosphere; standard cubic centimetre |
cc atm; scc | ≡ 1 atm × 1 cm³ | = 0.101 325 J |
| inch-poundforce | in lbf | ≡ g × 1 lb × 1 in | = 0.112 984 829 027 616 7 J |
| foot-pound force | ft lbf | ≡ g × 1 lb × 1 ft | = 1.355 817 948 331 400 4 J |
| calorie (20 °C) | cal20 °C | - | ≈ 4.1819 J |
| calorie (thermochemical) | calth | - | ≡ 4.184 J |
| calorie (15 °C) | cal15 °C | - | ≡ 4.1855 J |
| calorie (International Table) | calIT | - | ≡ 4.1868 J |
| calorie (mean) | calmean | - | ≈ 4.190 02 J |
| calorie (3.98 °C) | cal3.98 °C | - | ≈ 4.2045 J |
| litre-atmosphere | l atm; sl | ≡ 1 atm × 1 L | = 101.325 J |
| gallon-atmosphere(U.S.) | US gal atm | ≡ 1 atm × 1 gal (US) | = 383.556 849 013 8 J |
| gallon-atmosphere (Imperial) | US gal atm | ≡ 1 atm × 1 gal (Imp) | = 460.632 569 25 J |
| British thermal unit (thermochemical) | BTUth | ≡ 1lb/g × 1 calth × 1 °F/°C = 9.489 152 380 4 ÷ 9 kJ |
≈ 1.054 350 kJ |
| Britishthermal unit (ISO) | BTUISO | - | ≡ 1.0545 kJ |
| Britishthermal unit (63 °F) | BTU63 °F | - | ≈ 1.0546 kJ |
| Britishthermal unit (60 °F) | BTU60 °F | - | ≈ 1.054 68 kJ |
| Britishthermal unit (59 °F) | BTU59 °F | - | ≡ 1.054 804 kJ |
| Britishthermal unit (International Table) | BTUIT | ≡ 1lb/g × 1 calIT × 1 °F/°C | = 1.055 055 852 62 kJ |
| Britishthermal unit (mean) | BTUmean | - | ≈ 1.055 87 kJ |
| Britishthermal unit (39 °F) | BTU39 °F | - | ≈ 1.059 67 kJ |
| Celsiusheat unit (International Table) | CHUIT | ≡ 1 BTUIT × 1 °C/°F | = 1.899 100 534 716 kJ |
| cubicfoot of atmosphere; standard cubic foot | cu ft atm; scf | ≡ 1 atm × 1 ft³ | = 2.869 204 480 934 4 kJ |
| kilocalorie; large calorie | kcal; Cal | ≡ 1000 calIT | = 4.1868 kJ |
| cubicyard of atmosphere; standard cubic yard | cu yd atm; scy | ≡ 1 atm × 1 yd³ | = 77.468 520 985 228 8 kJ |
| cubicfoot of natural gas | - | ≡ 1000 BTUIT | = 1.055 055 852 62 MJ |
| horsepower-hour | hp·h | ≡ 1 hp × 1 h | = 2.6845 MJ |
| kilowatt-hir;Board of Trade Unit | kW·h; B.O.T.U. | ≡ 1 kW × 1 h | = 3.6 MJ |
| thermie | th | ≡ 1 McalIT | = 4.1868 MJ |
| therm (U.S.) | - | ≡ 100 000 BTU59 °F | = 105.4804 MJ |
| therm (E.C.) | - | ≡ 100 000 BTUIT | = 105.505 585 262 MJ |
| ton of TNT | tTNT | ≡ 1 Gcalth | = 4.184 GJ |
| barrelof oil equivalent | bboe | ≈ 5.8 MBTU59 °F | ≈ 6.12 GJ |
| tonof coal equivalent | TCE | ≡ 7 Gcalth | = 29.3076 GJ |
| tonof oil equivalent | TOE | ≡ 10 Gcalth | = 41.868 GJ |
| quad | - | ≡ 1015 BTUIT | = 1.055 055 852 62 EJ |
Energy can be expressed many ways. Two relationships allow us to freely convert between energy,
wavelength and frequency (see below). If you know any one of these three properties, you know the other two.
| Unit | Equivalent temperature measurements |
| Wavenumber (cm-1) |
A wavelength of energy that is also called a reciprocal centimeter. Wavenumbers are obtained when frequency is expressed in Hertz and the speed of light is expressed in cm/s. This unit is commonly used in infrared spectroscopy. |
| Kilojoules per mole (kJ/mol, kJ · mol-1) |
A Joule, J, is the SI unit of energy and is defined as one kg·m2/s2. The prefix "kilo" means 1,000, so one kJ = 1,000 J. As the energies associated with a single molecule or atom are quite small, we often find it easier to discuss the energy found in one mole of the substance, hence "per mole". To get the energy for one molecule, divide kJ/mol by Avogadro's number, 6.022×1023. |
| Kilocalories per mole (kcal/mol, kcal · mol-1) |
A calorie was originally defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius. One calorie = 4.184 J. One kcal = 1,000 cal. When we count calories in our food, we are actually referring to kilocalories; e.g. 1 dietary Calorie = 1,000 cal = 1 kcal. See the note in the previous entry for information about the mole part of this unit. |
| Nanometer nm |
The prefix "nano" means 1×10-9 = 0.000000001 = 1/1,000,000,000. Therefore, a nanometer refers to energy with a wavelength that is 1/1,000,000,000 th of a meter. Visible light is made of up electromagnetic radiation that has wavelengths ranging from roughly 300 to 800 nm. |
| Hertz (s-1, Hz, 1/s) |
A Hertz is a unit of frequency defined as a reciprocal second, s-1. For example, AC current cycles polarity 60 times per second in the U.S., so we could call this 60 Hz = 60 s-1. Human hearing has a frequency range from 20 Hz up to approximately 20,000 Hz. |
| Megahertz (MHz) |
The prefix "mega" means 1,000,000, so there are 1,000,000 Hz in one MHz. This is a typical frequency for radio equipment as well as high-tech scientific instruments such as magnetic resonance imaging (MRI, or NMR) scanners. |
| Electron Volt (eV) |
The electron volt is the energy that we would give an electron if it were accelerated by a one volt potential difference. 1 eV = 1,60217653×10-19 J. This term is most often used by physicists and electrochemists. |
| Here are the two relationships that relate energy, frequency and wavelength. The first is c = n · λ where c = the speed of light in vacuum (3.00×108 m/s), n = frequency and λ is wavelength. The second is E = h · n where E = energy, h is a special constant called Planck's constant (6.63×10-34 J · s) and n is again frequency. The second equation tells us that frequency is proportional to energy. Combining the two, we find that frequency and energy are inversely proportional to wavelength. |
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