An inventory packing system and method are described. In some examples, a plurality of items having various dimensions may be accessed. A plurality of trays having various height dimensions into which the plurality of items can be packed may be identified. The plurality of items may be grouped into one or more groups based on height. Allocated inventory trays may be searched to locate free space that can function as a packing location for a first item. If free space is not found in the allocated inventory trays, other inventory trays can be allocated, searched, and free space identified in one of the other inventory trays.