Method and device for calculating number of products

The invention discloses a method and device for calculating the number of products. The method comprises the steps of collecting product information of a to-be-purchased product, wherein the product information at least comprises cost information of the to-be-purchased product and the abnormal probability that the to-be-purchased product is abnormal; obtaining the demand quantity of the first object for the to-be-purchased products; based on the product information and the demand quantity, constructing a cost function corresponding to the first object, the cost function representing an association relationship between an initial purchase quantity of the to-be-purchased product purchased by the first object and cost consumed by the first object; determining the target number of the to-be-purchased products purchased by the first object based on the preset cost corresponding to the first object and the cost function, wherein the target number is the product number of the to-be-purchased products when the loss o