# Definition:Watt (Unit)

## Definition

The watt is the SI unit of power.

It is defined as being:

the rate at which work is done when the velocity of a body is held constant at $1$ metre per second against a constant opposing force of $1$ newton
the rate at which work is performed when an electric current of $1$ ampere flows across an electrical potential difference of $1$ volt.

### Symbol

$\mathrm W$

The symbol for the watt is $\mathrm W$.

Its $\LaTeX$ code is \mathrm W .

### Base Units

The SI base units of the watt are:

$\mathrm W := \mathrm {kg} \, \mathrm m^2 \mathrm s^{-3}$

where:

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

## Source of Name

This entry was named for James Watt (I).