Difference between Osmotic pressure and Osmotic potential

The movement of water molecules through a semi permeable membrane from the region of higher water concentration to the region of lesser water concentration is called osmosis.
Osmotic Pressure (OP): The actual pressure, that develops in a solution, when it is separated from pure water by means of semipermeable membrane. It depends upon concentration, ionization, hydration and temperature. It is measured in terms of atmosphere (atm).

OP=miRT

where, m= Molar concentration, i= ionization constant,

 R= Gas constant and T= temperature.

Osmotic potential: It is the decrease in chemical potential of pure water due to the presence of solute particle in it.

  ψs= CRT

 (It always have negative value)

Where C = concentration of solute particle, R = gas constant and T= temperature.
Osmotic pressure vs Osmotic potential

Osmotic pressure:

1. It is the pressure which develops in an osmotic system due to entry of water into it.

2. It develops only in a confirmed system.

3. The value is positive through numerically eual to osmotic potential.

Osmotic potential:

1. It is lowering of free energy of water in a system duet o the presence of solute particles.

2. Osmotic potential is present whether the solution occurs in a confined system or an open system.

3.The value is negative through it is numerically equal  to osmotic pressure.
Learn more: Difference between Osmosis and Diffusion (Osmosis vs Diffusion)