The general size of a bag is typically around 10x8x5. This dimensions are the approximate standard for most bags, such as messenger bags, backpacks and tote bags. The measurements refer to length x width x depth in inches, with the maximum capacity determined by those measurements. For example, if your bag measures 10” x 8” x 5” it will hold up to 40 liters or 2441 cubic inches of items. It's important to measure carefully before purchasing any kind of bag so you can make sure it fits all your belongings comfortably and securely!