Deadweight tonnage (also known as deadweight; abbreviated to DWT, D.W.T., d.w.t., or dwt) or tons deadweight (TDW) is a measure of how much weight a ship can carry, not its weight, empty or in any degree of load.
In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is assigned.
The displacement or displacement tonnage of a ship is its weight, expressed in long tons of water its hull displaces.
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a chemical formula.
Gross tonnage (often abbreviated as GT, G.T. or gt) is a nonlinear measure of a ship's overall internal volume.
The International Maritime Organization (IMO), known as the Inter-Governmental Maritime Consultative Organization (IMCO) until 1982, is a specialised agency of the United Nations responsible for regulating shipping.
The Moorsom System is a method created in Great Britain of calculating the tonnage or cargo capacity of sailing ships as a basis for assessing harbour and other vessel fees.
Net register tonnage (NRT, nrt, n.r.t.) is a ship's cargo volume capacity expressed in "register tons", one of which equals to a volume of.
Net tonnage (often abbreviated as NT, N.T. or nt) is a dimensionless index calculated from the total moulded volume of the ship's cargo spaces by using a mathematical formula.