A printing system that enables a user to determine the number of sheets that a printing apparatus can print, the number of sheets corresponding to a power supply source that supplies power to the printing apparatus, in any power mode. The printing apparatus performs printing in any of a plurality of power modes including (i) a first power mode in which the printing apparatus is supplied with power from the battery, and (ii) a second power mode in which the printing apparatus is supplied with power supplied from both the battery and an external power supply. In the second power mode, the number of sheets that the printing apparatus can print is calculated based on the remaining battery level of the battery and an amount of power supplied from the external power supply.