LCL is billed on the revenue ton: one cubic metre or one metric tonne, whichever is greater. So 12 cbm weighing 5.4 tonnes is 12 R/T, and 5 cbm weighing 8 tonnes is 8 R/T. The freight is that figure times the per-ton rate, plus a stack of fixed charges — CFS, documentation, handling — that do not shrink when the shipment does. An FCL box is one price whatever goes inside it.
That is why the answer is a line crossing a flat, not a rule of thumb. LCL rises with volume; FCL sits still. The crossover moves every time either rate moves, and it moves with density too — heavy cargo hits the tonne side of the revenue ton and reaches the crossover on fewer cubic metres than the folklore "13 to 15 cbm" suggests.
Two things the arithmetic will not tell you and the quote should. A box is normally faster, because LCL waits for the consolidator to fill it and then waits again for deconsolidation at the CFS at the other end — often a week each way. And a box is safer: nobody else's cargo is stacked on yours, and no other shipper's paperwork can hold your container at customs. On a shipment near the crossover, those two facts are worth more than the difference in the freight.
There is no universal figure — it is wherever your LCL line crosses your box price, which on typical trans-Pacific numbers lands somewhere between 12 and 18 cbm and moves every time either rate does. Work it out on the two rates in front of you. And bear in mind that below the crossover the box is often still the right advice, because it is faster and cannot be delayed by another shipper's customs problem.
The greater of one cubic metre or one metric tonne, written R/T or W/M. It is the ocean equivalent of chargeable weight: the carrier bills whichever of space and mass costs them more. Most trades tie them at 1000 kg to the cubic metre, so cargo denser than a tonne per cube pays on weight and everything lighter pays on space.
Almost always, and the delay is at the ends rather than on the water. The consolidator holds the cargo until the container is full, and at destination the box goes to a CFS to be stripped before anything is released. Five to ten days each side is normal. On a deadline, that is usually the whole argument, whatever the freight says.
Usually one of three things. The cargo re-measured larger at the CFS — pallets and overhang get measured, cartons on a packing list do not. Destination handling at the consignee end was outside the quoted scope. Or the shipment fell short of a minimum and was billed at 1 R/T. All three are avoidable at quoting time by stating the measurement basis, the scope at both ends, and the minimum, in writing.
Yes, comfortably — a 20GP is about 33 cbm on paper and around 28 loaded, so 20 cbm leaves room. What catches people is the other limit: 20 cbm of tiles or machinery can pass 28 tonnes and exceed the payload while the box still looks half empty. Check both, which is what the "fills the box" row above does.
Cargo-Stack reads the enquiry, prices it against your own rates, and drafts the quote — with this arithmetic underneath it. Same maths, no retyping.
Try it on a real enquiry