Freight Ton (Revenue Ton)
A Freight Ton (or revenue ton) is the unit on which ocean and break-bulk freight is charged, taken as the greater of the shipment's weight or its volume — the “weight or measure” (W/M) basis. One freight ton is 1,000 kg (1 tonne) of weight or 1 cubic metre of volume, and the carrier bills whichever yields more.
This exists because a ship can run out of either weight capacity or space, so carriers protect their revenue by charging on whichever is limiting for a given cargo: dense, heavy cargo is charged by weight, while light, bulky cargo is charged by volume. Freight quoted "per freight ton" or "W/M" therefore requires knowing both the weight and the measurement of the cargo. It is the sea-freight counterpart to the chargeable weight concept used in air cargo, and central to costing less-than-container and break-bulk shipments.
Because ships can fill up on either weight or space, freight is billed on whichever is greater — so a shipment's cost depends on both its weight and its volume. Miss this and an LCL or break-bulk quote can be badly wrong. The freight ton is the basic unit behind sea-freight pricing, mirroring chargeable weight in air.
What is a freight ton?
The greater of one tonne of weight or one cubic metre of volume — the "weight or measure" (W/M) basis for charging freight.
Why charge on weight or measure?
A ship can be limited by weight or by space, so carriers bill on whichever is greater to protect revenue for both dense and bulky cargo.