Kiloelectronvolts to Kilowatt-hours (keV to kWh)

1 kiloelectronvolt equals 4.45049065×10⁻²³ kilowatt-hours exactly.

1 kiloelectronvolt = 4.45049065×10⁻²³ kilowatt-hours

How to convert kiloelectronvolts to kilowatt-hours

To convert kiloelectronvolts to kilowatt-hours, multiply the number of kiloelectronvolts by 4.45049065×10⁻²³. This factor is exact. To go the other way, multiply kilowatt-hours by 2.246943267×10²² (rounded).

kilowatt-hours = kiloelectronvolts × 4.45049065×10⁻²³

Example: 10 kiloelectronvolts = 4.45049065×10⁻²² kilowatt-hours.

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

Kilowatt-hour (kWh)

Metric (SI)Current unit

3.6 million joules, the energy used by a 1,000-watt appliance in an hour. The billing unit for household electricity.

Before it was a line on every power bill, the kilowatt-hour had a British nickname: the Board of Trade unit, abbreviated B.T.U. after the government body that regulated the electricity industry until 1942, when the Ministry of Power took over. In India it is still often called simply a unit, and a million of them, written MU, is a gigawatt-hour.

A kilowatt-hour is the energy of a 1 kW device running for an hour, which is 3.6 MJ, or about 3,412 British thermal units. A 100 W television watched for 10 hours uses one, and boiling a liter of water in an electric kettle takes about 0.1. In 2020 the average US household used 893 kWh a month, an average continuous draw of about 1.22 kW.

Utilities multiply the kilowatt-hours consumed by a price per kWh, and larger customers may also pay for peak demand. One common error is writing kW/h, which would mean kilowatts per hour, a rate of change of power, not energy.

1 kilowatt-hour = 3,600,000 joules (exactly).

Sources: Wikipedia: Kilowatt-hour; Wikipedia: British thermal unit; Wikipedia: Watt-hour

Related conversions

See all energy units.