A computing device determines the contents of one or more assortment packs for an online distribution center (“DC”) based on pre-defined store assortment packs. The computing device selects a group of store assortment packs that fulfill the requirements of an online distribution center for a first set of items that are offered for sale at both the retail stores and the online store. The computing device may further identify a second set of items that are not offered for sale at the retail stores, such as “online only” items, and which therefore are not included within any of the store assortment packs. The computing device optimizes the contents of the selected group of store assortment packs to ensure that the second set of items can be fit into the selected group of store assortment packs.