• Offhand, it appears pack capacity and volume liters are identical measurements, expressed in standard (cubic inches) and metric (liters). Pack volume appears to be a classification for sorting, in that many packs will fit in the range of volumes listed under that spec. Pack Volume would be used to search for a particular size class of pack, like if I knew I wanted something with 25L or 55L depending on whether I wanted a daypack or overnight pack, or a larger pack for longer treks.
    Answered on 7/2/2014 10:49:07 AM by dubyam from Huntsville, AL