What is the volume of a briefcase?

Mil Standard Injection Molded Briefcase Inside Dimensions: 18 1/2 in. x 13 in. x 4 3/4 in. Outside Dimensions: 20 in. x 15 1/2 in. x 5 3/4 in.

The volume is L * W * H, therefore, the volume of this military standard briefcase is: 18 1/2 in. * 13 in. * 4 3/4 in. which equals 1142.375 cubic inches. This is also a little over a half of a cubic foot or to be exact .661 cubic feet.