An image forming apparatus includes a receiving unit configured to receive an input regarding a print process from a user; a setting unit configured to set the apparatus to normal or energy saving mode based on the input from the user, the normal mode causing the apparatus to be operated by the power supplied from a power supply unit, the energy saving mode causing the apparatus to be operated by the power supplied from the power supply unit or a secondary battery so that power consumption of the apparatus is less than that in the normal mode; a calculation unit configured to calculate a charging amount of the battery based on an energy saving time for which the apparatus has been in the energy saving mode; and a charging unit configured to charge the battery with the power from the power supply unit by the charging amount.