The O'Neill Girls 18 L is a backpack for girls that you use for school or work. You put your laptop up to 13.3 inches in the separate laptop compartment. You also have space in the main compartment for some books and other documents. In the front pocket you put your case, sunglasses and other accessories.Note: the size of your laptop, such as 15 inch or 17.3 inch, is the size of the screen, not of your entire laptop. If the edge around your screen is wide, choose a laptop compartment in a larger size to be sure. This way you know for sure that your laptop will fit.