Abstract: Provided is a reward calculation system including at least one processor configured to acquire payment information about a payment of a transaction object traded on a user terminal used by a user; acquire a user attribute of the user; calculate an estimated reward potentially provided to the user terminal, based on at least the payment information and the user attribute; cause the user terminal to display the estimated reward; and acquire, after the estimated reward is displayed, receipt information included in a receipt image in which a receipt issued for a transaction of the transaction object is displayed.