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The joule is the SI unit of energy.

It is defined as being:

the energy transferred to (or work done on) a body when a force of $1$ newton acts on that body in the direction of the force's motion through a distance of $1$ metre
the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second.


$1 \, \mathrm J = 1 \, \mathrm N \, \mathrm m$

Conversion Factors

\(\ds \) \(\) \(\ds 1\) joule
\(\ds \) \(=\) \(\ds 10^7\) ergs


$\mathrm J$

The symbol for the joule is $\mathrm J$.

Its $\LaTeX$ code is \mathrm J .

Base Units

The SI base units of the joule are:

$\mathrm J := \mathrm {kg} \, \mathrm m^2 \mathrm s^{-2}$


$\mathrm {kg}$ denotes kilograms
$\mathrm m$ denotes metres
$\mathrm s$ denotes seconds (of time).

Source of Name

This entry was named for James Prescott Joule.