Kilocalories to Megaelectronvolts (kcal to MeV)

1 kilocalorie equals 2.611447397×10¹⁶ megaelectronvolts (rounded).

1 kilocalorie = 2.611447397×10¹⁶ megaelectronvolts

How to convert kilocalories to megaelectronvolts

To convert kilocalories to megaelectronvolts, multiply the number of kilocalories by 2.611447397×10¹⁶. The factor is rounded to 10 significant digits. To go the other way, multiply megaelectronvolts by 3.829294058×10⁻¹⁷ (rounded).

megaelectronvolts = kilocalories × 2.611447397×10¹⁶

Example: 10 kilocalories = 2.611447397×10¹⁷ megaelectronvolts.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Kilocalorie (kcal)

ScientificTraditional unit (still used in some regions)

1,000 thermochemical calories (4,184 J). The 'Calorie' on food labels in North America.

Marcellin Berthelot separated the gram calorie from the kilogram calorie in 1879, and the American chemist Wilbur Atwater adopted a capital-C Calorie for the large unit in 1887 in a widely read article on the energy in food. Joseph Howard Raymond proposed the term kilocalorie in his 1894 textbook. The two names now describe the same quantity, 1,000 small calories, which at the thermochemical value is 4,184 J or 4.184 kJ.

Food labels carry the unit today, though practice differs by region. North American labels use kilocalories almost exclusively, European labels show kilojoules and kilocalories together under EU Regulation 1169/2011, and Chinese labels give kilojoules only. Typical energy contents are about 9 kcal per gram for fat, about 4 for carbohydrate and protein, and about 7 for alcohol. In electrical terms, 4,184 J works out to about 1.162 watt-hours, since one watt-hour is 3,600 J. NIST also lists a kilocalorie based on the International Table calorie, which is 4,186.8 J.

1 kilocalorie = 4,184 joules (exactly).

Sources: Wikipedia: Calorie (includes kilocalorie); NIST SP 811, Appendix B.8 (energy conversion factors)

Megaelectronvolt (MeV)

ScientificCurrent unit

One million electronvolts. The scale of nuclear reactions.

Nuclei trade energy in millions of electronvolts. In binding-energy tables, medium-mass nuclei hold about 8.8 MeV per nucleon, with iron-56 listed at 8.7906 MeV. Fusing deuterium with tritium releases about 17.53 MeV per reaction, while an electron and positron annihilating give 1.022 MeV. One megaelectronvolt equals 1.602176634 x 10^-13 J, so even these reactions involve only tiny amounts of energy per event.

Per atom, though, the scale is enormous. A 17.53 MeV reaction is more than a million times the 1 to 10 eV that binds atoms into molecules, which is why nuclear fuels hold so much more energy than chemical ones. The electron's rest energy is 0.511 MeV and the muon's is 105.7 MeV, so the unit also serves for particle masses. A thousand MeV make one GeV, the next step up.

1 megaelectronvolt = 1.602176634×10⁻¹³ joules (exactly).

Sources: Wikipedia: Nuclear binding energy; Wikipedia: Electronvolt

Related conversions

See all energy units.