According to one of aspects, a mobile device, includes: a motion sensor module configured to detect a motion factor a communication module configured to receive a plurality of operation factors used for an operation of an activity factor indicating an activity amount and respective dates and times at which the operation factors are measured and a control module configured to calculate the activity factor indicating the activity amount using the operation factors received through the communication module and a value based on the motion factor detected by the motion sensor module when the operation factors are received.
