Consolidator of ocean containers charges per CBM/kg for LCL containers. However, it is difficult to manage small cargo at consolidation. So generally, if a shipment is smaller than 1 CBM or 1000kgs, the consolidator does not accept it. Check out ocean freight for LCL cargo.
So we can say the smallest cargo acceptable to be shipped via Sea is 1 Cubic Metre (CBM) or 1000 kgs. This is minimum required sum of all your boxes for same source and destination in the shipment.
At Portlogy, we accept cargo where total volume is less than 1CBM or weight less than 1000 Kgs. However, it will be charged as 1 CBM.
Know more about LCL cargo.