A computer implemented method for packing an item package in a container, comprising: under control of one or more computing systems configured with executable instructions, determining custom container dimension values for forming at a materials handling facility a custom container for containing the item package, the custom container dimension values dependent at least in part upon the physical characteristics associated with the item; determining a size range for the custom container based at least in part on the determined custom container dimension values; identifying a custom container forming device configured to form custom containers having dimension values corresponding to the determined size range; routing the item package to a pack station; causing a custom container to be formed by the identified custom container forming device based at least in part on dimension values associated with the item package; and packing at the pack station the item package in the formed custom container, wherein identifying a custom container forming device includes identifying a plurality of item packages having a same size range as the item package and wherein causing a custom container to be formed by the identified custom container forming device further includes causing, for each of the identified plurality of item packages, a custom container to be formed by the identified custom container forming device. under control of one or more computing systems configured with executable instructions, determining custom container dimension values for forming at a materials handling facility a custom container for containing the item package, the custom container dimension values dependent at least in part upon the physical characteristics associated with the item; determining a size range for the custom container based at least in part on the determined custom container dimension values; identifying a custom container forming device configured to form custom containers having dimension values corresponding to the determined size range; routing the item package to a pack station; causing a custom container to be formed by the identified custom container forming device based at least in part on dimension values associated with the item package; and packing at the pack station the item package in the formed custom container, wherein identifying a custom container forming device includes identifying a plurality of item packages having a same size range as the item package and wherein causing a custom container to be formed by the identified custom container forming device further includes causing, for each of the identified plurality of item packages, a custom container to be formed by the identified custom container forming device. determining custom container dimension values for forming at a materials handling facility a custom container for containing the item package, the custom container dimension values dependent at least in part upon the physical characteristics associated with the item; determining a size range for the custom container based at least in part on the determined custom container dimension values; identifying a custom container forming device configured to form custom containers having dimension values corresponding to the determined size range; routing the item package to a pack station; causing a custom container to be formed by the identified custom container forming device based at least in part on dimension values associated with the item package; and packing at the pack station the item package in the formed custom container, wherein identifying a custom container forming device includes identifying a plurality of item packages having a same size range as the item package and wherein causing a custom container to be formed by the identified custom container forming device further includes causing, for each of the identified plurality of item packages, a custom container to be formed by the identified custom container forming device.