Tonnage - Wikipedia Tonnage is a measure of the capacity of a ship, and is commonly used to assess fees on commercial shipping The term derives from the taxation paid on tuns or casks of wine In modern maritime usage, "tonnage" specifically refers to a calculation of the volume or cargo volume of a ship
Ton vs. Tonnage — What’s the Difference? A ton is a unit of weight, while tonnage refers to the volume or carrying capacity of a ship or the weight of cargo a ship carries