Kiloelectronvolts to Kilojoules (keV to kJ)

1 kiloelectronvolt equals 1.602176634×10⁻¹⁹ kilojoules exactly.

1 kiloelectronvolt = 1.602176634×10⁻¹⁹ kilojoules

How to convert kiloelectronvolts to kilojoules

To convert kiloelectronvolts to kilojoules, multiply the number of kiloelectronvolts by 1.602176634×10⁻¹⁹. This factor is exact. To go the other way, multiply kilojoules by 6.241509074×10¹⁸ (rounded).

kilojoules = kiloelectronvolts × 1.602176634×10⁻¹⁹

Example: 10 kiloelectronvolts = 1.602176634×10⁻¹⁸ kilojoules.

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

About these units

Kiloelectronvolt (keV)

ScientificCurrent unit

1,000 electronvolts. X-ray photon energies are in this range.

X-rays are the usual home of the keV. Wilhelm Roentgen discovered them on 8 November 1895, and their photon energies span about 100 eV to 100 keV. Photons above roughly 5 to 10 keV count as hard X-rays, while lower ones are soft. Medical diagnostic tubes run at 20 to 150 kilovolts, which sets the highest photon energies of a radiograph at about 20 to 150 keV. One keV is 1.602176634 x 10^-16 J.

Fusion research uses it for temperature. A magnetic confinement plasma at about 15 keV corresponds to roughly 174 million kelvin. Compared with the electronvolt, a kiloelectronvolt is a thousand times larger, so it lies well above the 1 to 10 eV of chemical bonds, yet far below the millions of electronvolts released in nuclear reactions.

1 kiloelectronvolt = 1.602176634×10⁻¹⁶ joules (exactly).

Sources: Wikipedia: X-ray; Wikipedia: Electronvolt

Kilojoule (kJ)

Metric (SI)Current unit

1,000 joules. Food labels in many countries give energy in kilojoules.

Most food labels around the world express energy in kilojoules, which is the calorie's long retirement in action. The calorie came out of heat measurement, and the 1948 CGPM resolution stated that the joule should be preferred as the unit of heat. Labels that still show kilocalories alongside kilojoules rely on the thermochemical calorie of exactly 4.184 joules, so one kilocalorie is about 4.184 kJ.

The kilojoule is a convenient size for a body's daily bookkeeping. A person at rest uses about 5,000 kJ, or roughly 1,200 kcal, per day, and the recommended intake for a moderately active woman is given as 2,000 food calories, which is about 8,400 kJ.

Smaller physical comparisons land in the same range. One watt-hour is 3.6 kJ, a British thermal unit is about 1.1 kJ, exploding a gram of TNT releases about 4.2 kJ, and an alkaline AA battery holds about 9 kJ.

1 kilojoule = 1,000 joules (exactly).

Sources: Wikipedia: Kilojoule; Wikipedia: Joule; Wikipedia: Orders of magnitude (energy)

Related conversions

See all energy units.