Energy condition for isothermal reversible magnetoelectric switching of exchange bias was investigated using Pt/Co/Au/Cr 2 O 3 /Pt stacked films with different thicknesses of the antiferromagnetic layer (t AFM ). We discussed the effective magnetic anisotropy energy of the antiferromagnetic layer (K AFM eff), the interface exchange coupling energy (J INT ), and the offset electric field (E 0 ). The dependence of K AFM eff on t AFM suggested that the magnetic domain wall motion significantly influenced the switching of the electric-field-induced magnetization similar to an ordinal ferromagnet. Below 0.025 mJ/m 2 , J INT was equal to the exchange anisotropy energy (J K ), and above 0.025 mJ/m 2 , J INT exceeded J K , suggesting that J K is restricted by the magnetic domain wall energy. The dependence of E 0 on t AFM revealed that E 0 mainly arose from the interfacial uncompensated antiferromagnetic moment. The obtained results suggest that the energetic interpretation of static switching of electric-field-induced magnetization in Cr 2 O 3 was similar to that of the ordinary ferromagnetic materials.