The degree of dissociation $\alpha$ of a weak electrolyte at a given concentration is related to its molar conductivity $\Lambda_m$ and limiting molar conductivity $\Lambda^\circ_m$ by:

At a finite concentration only a fraction $\alpha$ of the electrolyte dissociates, so $\Lambda_m = \alpha\,\Lambda^\circ_m$. This gives $\alpha = \Lambda_m / \Lambda^\circ_m$, an Arrhenius-style result used widely to estimate the dissociation constant of weak acids and bases via Ostwald's dilution law.