The joule (/l, l/ jowl, jool;[1][2][3] symbol: J) is a derived unit of energy in the International System of Units.[4] It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of the force's motion through a distance of one metre (1 newton-metre or N⋅m). It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).[5][6][7]

Unit systemSI derived unit
Unit ofEnergy
Named afterJames Prescott Joule
1 J in ...... is equal to ...
   SI base units   kgm2s−2
   CGS units   1×107 erg
   Watt-seconds   1Ws
   kilowatt-hours   2.78×10−7 kW⋅h
   kilocalories (thermochemical)   2.390×10−4 kcalth
   BTUs   9.48×10−4 BTU
   electronvolts   6.24×1018 eV