The degree of dissociation is the fraction of the original solute molecules that have dissociated. It is usually indicated by the Greek symbol . There is a simple relationship between this parameter and the van 't Hoff factor. If a fraction  of the solute dissociates into  ions, then
For example, the dissociation KCl  K + Cl yields  ions, so that .
For dissociation in the absence of association, the van 't Hoff factor is: