20” tall x 14” wide (at base) 6 to 7” deep (not expanded) Zipper expansion gives another 2” depth all around. When stuffed and expanded, bag measures roughly 20 x 14 x 9 Heavy padding on back Padded shoulder and waste straps Snap buckle adjustable shoulder and waste straps Two front compartments with ID holder for small items. Large main inner compartment with mesh and zipper compartments.