What Is Tonnage in Shipping? Every Type of Tonnage Explained

Tonnage in shipping is any of several measurements that describe cargo weight, cargo volume, or vessel capacity, and the word means different things depending on context. A metric ton is 1,000 kilograms (2,204.6 lbs), a short ton is 2,000 lbs, and a long ton is 2,240 lbs, while a vessel's gross tonnage measures internal volume where one gross ton equals 100 cubic feet of enclosed space. The reason this matters to a shipper is money: the type of tonnage applied to your cargo determines how the freight is priced, how a port assesses its fees, and how much a vessel can actually carry.

This guide separates the three families of tonnage, weight-based, volume-based, and vessel-capacity, then covers TEU and the one measure that actually drives most ocean and LTL quotes: the revenue ton. It is written for the shipper who needs to read a quote correctly, not memorize maritime trivia.

Weight-Based Tonnage

Weight-based tonnage is the most intuitive family, but it carries a trap: "ton" means three different weights depending on who is using it. Getting these mixed up on an international quote can throw a calculation off by more than 10 percent.

• Metric ton (tonne): 1,000 kilograms, or 2,204.6 lbs. This is the standard weight unit in international shipping, and when someone says "ton" in an export or ocean context, they almost always mean this.
• Short ton: 2,000 lbs (907.2 kg). This is the standard ton in the United States and shows up mostly in domestic freight and bulk commodity pricing.
• Long ton: 2,240 lbs (1,016 kg). The traditional British ton, still seen in some maritime and bulk contexts but increasingly replaced by the metric ton.

The practical rule is to confirm which ton a quote uses before comparing two carriers, because a price "per ton" is meaningless until you know whether the ton is 2,000, 2,204.6, or 2,240 lbs. On heavy chemical and mineral freight, the gap compounds across a full vessel parcel.

Volume-Based Tonnage

Volume-based tonnage exists because not all cargo is dense. A container of pillows weighs almost nothing but fills the box, so charging purely by weight would let it ride nearly free. Ocean and LTL carriers solve this by measuring volume in tons too.

Measurement Ton (Freight Ton)

A measurement ton equals one cubic meter of cargo space, roughly 35.3 cubic feet. When cargo is light relative to its size, the carrier prices by the space it occupies rather than its weight. This is why bulky, low-density freight can cost more to ship than its weight alone would suggest.

Revenue Ton

The revenue ton is the greater of the weight ton or the measurement ton on a given shipment, and it is the single most important tonnage concept for a shipper to understand. Carriers compare the two and bill on whichever yields more revenue: dense cargo pays by weight, light and bulky cargo pays by volume. This is the same weight-or-volume logic that governs LTL freight class, which we cover in our guide to how much LTL freight costs.

Vessel Capacity Tonnage

Vessel-capacity tonnage describes the ship itself rather than your cargo, and ports, canals, and regulators use it to assess fees and apply safety rules. Four measures matter.

For a freight shipper, deadweight tonnage is the number that matters, because it indicates how much cargo a vessel can actually move. A large dry bulk carrier might carry a DWT above 200,000 metric tons, while a large container vessel can show a gross tonnage above 150,000.

TEU and Container Tonnage

For container shipping, capacity is measured in TEU rather than tons. TEU stands for Twenty-foot Equivalent Unit, and it is the standard way to express how many containers a vessel or a terminal can handle.

• One TEU equals one standard 20-foot container, the baseline unit of measure.
• One 40-foot container equals 2 TEU, so a vessel rated at 10,000 TEU does not carry 10,000 forty-foot boxes.
• Modern ultra-large container vessels carry 20,000 or more TEU, which is why a single sailing can move an enormous volume of goods.

TEU is a capacity and throughput measure, not a weight measure, so it sits alongside tonnage rather than replacing it. Your individual container still gets priced on the revenue ton or on a flat box rate depending on whether you book FCL or LCL, a distinction we explain in our overview of container ocean freight for chemical shippers.

Why Tonnage Matters for Your Freight Cost

Tonnage is not academic; it is the basis of the invoice. The wrong assumption about which ton applies can make one carrier's quote look cheaper than another's when it is actually more expensive once converted to a common unit.

• On ocean freight, the carrier prices the revenue ton, so light cargo can cost more than its weight suggests and dense cargo is capped by volume.
• On LTL, weight and density together set the freight class, which then drives the rate, the same weight-or-volume principle under a different name.
• On port and canal fees, gross and net tonnage of the vessel flow into terminal handling and canal dues that can appear as surcharges on your bill.

Reading a quote correctly means knowing which tonnage the carrier applied and converting every competing quote to the same unit before you compare. A forwarder who quotes you cleanly will tell you exactly which ton drove the number.

How Total Connection Uses Tonnage in Your Quotes

Total Connection has quoted ocean and international freight for shippers since 1995, and we price on the revenue ton, the greater of weight or volume, so the number you see matches how the carrier actually bills. As an independent, non-asset forwarder and NVOCC (license 026203NF), we convert between metric tons, short tons, measurement tons, and TEU so your quotes are clear and directly comparable across carriers and modes.

Tonnage shows up across everything we move: ocean FCL and LCL, air, drayage, truckload, and the liquid bulk and hazmat freight that is our home turf. The same team that converts your ocean revenue ton also handles the inland leg, the customs entry, and the warehousing. To go deeper, see our guides to container ocean freight and LTL freight cost, then visit our ocean freight service. For a clear, converted quote on your lane, call 732-817-0401 or request a quote.