Large

Large runs 14 to 16 inches across and holds 12 to 18 liters. A 16 inch laptop measures about 14 by 9.8 inches. That means a 15 inch bag takes it only when the internal width is usable and the sleeve is padded. Alongside the machine you can fit letter files, a lunch box, a folded jacket and a pair of flat shoes.

Empty weight becomes the deciding number. A structured leather bag in this band starts around 1.2 kg and can reach 1.6 kg before you put anything in. Add a laptop with its charger and that is another 2 kg. Four kilograms on one shoulder buys you roughly ten minutes of comfort. That is why bags this size earn their keep with backpack straps or a wide crossbody rather than a short handle.

Two details separate a good one. The laptop sleeve should be suspended, meaning its base sits about an inch above the base of the bag. Setting the bag down hard then lands the shock on the bag and not the machine. The strap should measure at least an inch across where it crosses the shoulder, wider still if it carries no padding. Pushing the same load through a half inch strap concentrates pressure into a line. Metal feet on the underside keep the base off wet ground and stop the corners wearing through first.