# ampere per square metre

##### SI coherent derived unit
Name Symbol Derived quantity
ampere per
square metre
m−2 A current density

### Definition

The ampere per square metre, symbol m−2 A, is the SI coherent derived unit of current density.

An electric current of one ampere flowing through a cross-sectional area of one square metre of a conductor has a current density of one ampere per square metre.

### Electromagnetism

Current density is the electric current per unit area of cross section.

The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the charges at this point.