Osmolar concentration

What is osmolar concentration?

Osmolarity is a concept related to solutions that indicates the osmolar concentration, defined as the number of osmoles per liter of solution.

Osmol means the number of particles in the molecular weight of undissociated solute.


  • Glucose (does not dissociate) : 1 osmol = 1 mole = 180 gr of glucose
  • KCl (if dissociated): 2 osmoles = 1 mole = 74.5 gr of KCl


It is frequently used in physiological studies of diffusion through cell membranes, since the osmotic pressure is proportional to the number of ions or molecules present in the solution.