The gravitational potential ($\Phi$ or $V$) is the gravitational potential energy per unit mass.
$\Phi$ at a point is defined as the work done by a gravitational field on a unit mass in bringing the mass from infinity to the point in question. The potential is measured in $\text{ J}\text{ kg}^{-1}$ or $\text{ kg m}^2\text{ s}^{-2}$.
The equation for the gravitational potential is: $$\Phi=V = \frac{U}{m} = -\frac{GM}{r}$$
$r=$distance from mass $M$; $G=$universal gravitational constant.