A planning method for planning to order a product, the planning method being executed by a computer, the planning method includes: generating a predicted value of a demand of the product at each plurality of prices based on a selling price and a number of sales in association with each other for each past sale date; calculating an order quantity that yields a highest profit, for each of the plurality of prices, using the predicted value of the demand of the product at the plurality of prices; storing, for the plurality of prices, the calculated order quantity and a profit in association with each other into a memory; and identifying a combination of a price and an order quantity that yields the highest profit, with reference to the memory.