According to one embodiment, a calculation system includes a detector, a combiner, and a duration calculator. The detector refers to a plurality of images of an object imaged from mutually-different angles, detects the object in each of the images, and calculates a provisional position of the object in a coordinate system for each of the images. The coordinate system is prescribed. The combiner calculates a combined position of the object in the coordinate system by using the calculated plurality of provisional positions. The duration calculator refers to process information and a plurality of execution regions and calculates a duration of at least a portion of a plurality of processes based on the combined position and the execution regions. The process information includes information relating to the processes. The execution regions are represented using the coordinate system. The processes are executed in the execution regions.