We report atomic-scale simulations of the structure and formation energies of jog pairs on edge dislocations in magnesium oxide (MgO). The atomic configurations of elementary jogs of height and super-jogs of height are fully characterized showing that stable jogs spread in {111}. Besides, our simulations confirm that elementary jogs carry an electric charge ± q/2 where q is the charge of a Mg ion, while super-jogs are charge-neutral. The computation of the formation energy reveals the predominance of charged elementary jogs. This offers new insight into the mechanisms for dislocation climb in MgO.