Gross Tonnage

Gross Tonnage (GT) is a type of volumetric tonnage for ships, referring to the total volume of all enclosed spaces on a vessel, with 1 ton equivalent to 100 cubic feet (or 2.83 cubic meters). It is used to measure ship size and serves as the basis for ship registration, port charges, canal tolls, insurance, and maritime regulations (such as safe manning). Usage scenarios include: ship sale and purchase, chartering, port berthing, canal transit (e.g., Suez Canal), and ship surveys. Note: Gross Tonnage is a volumetric ton, dimensionless (or written as GT), and differs from weight tons (such as Deadweight Tonnage DWT, Displacement Tonnage); it also differs from Net Tonnage, which deducts non-revenue spaces like crew quarters and engine rooms. Foreign trade practitioners should note: in charter parties, bills of lading, and port charges, Gross Tonnage is often cited but should not be confused with cargo-carrying capacity. For example, a container ship with 50,000 GT may have a deadweight tonnage of 60,000 tons. Correct understanding aids cost calculation and compliance.