How do we derive this forumla I=nqAv for current?

[Elbraido]

Can someone tell or lead me to how we derive this formula I=nqAv for current?

 

[Lord Jestocost]

Regarding $I$ as the electric current flowing in a wire:
$n$ is the electron density, $A$ the cross sectional area of the wire, $v$ (or $v_d$) the drift velocity of the electrons and $q$ (or $e$) the charge of an electron.
See http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html