Pressure Gradient is defined as the change in pressure per unit distance. In other words pressure change over a unit distance is known as Pressure Gradient.
Mathematically,
Pressure Gradient = Pressure / Distance.
Dimensional Formula of Pressure = M1L-1T-2
Dimensional Formula of Distance= M0L1T0
Substituting the values in the given equation we get,
Dimensional Formula of Pressure Gradient = M1L-2T-2
SI unit of Pressure Gradient is Nm-3