What is a M3? December 13, 2023December 13, 2023 by vivian When shipping by sea, the term "M3" often appears in shipping information or quotations. Do you know what M3 (cubic meter) is? M3 – cubic meters is the volume that your cargo can fill in a limited space, 1 CBM = 100CM (width) x 100CM (length) x 100CM (height), which is also the volume of a standard card board. Example: The length, height and width of the cargo are 2.5 meters, 1.5 meters and 3 meters respectively The cargo volume is 2.5X 1.5 X 3.00 = 11.25 M3