Convert Ton Register (ton reg) to Barrel (US) (bbl (US)) instantly.
About these units
Ton Register (ton reg)
A register ton, or ton register, is a unit of volume, not mass, equal to 100 cubic feet. It is used in maritime contexts to measure the internal capacity of ships—specifically cargo-carrying volume, not weight. Ship registries rely on register tons to calculate taxes, port fees, and cargo classifications. The unit dates back to 19th-century maritime law, where consistent volumetric measurement was critical for international shipping regulation. Despite changes in global trade and containerization, register tons remain important for historical vessel documentation, as well as for understanding older merchant and naval ship specifications.
Barrel (US) (bbl (US))
The US barrel is a unit with multiple definitions depending on the industry, though the most common general-purpose US barrel is 31.5 US gallons, used historically for dry goods, ale, and various agricultural products. In practice, the US barrel arose from traditional cask-making, where wooden barrels of different shapes were used for storage and transport. Because their capacity varied widely, different industries standardized the barrel at different volumes. Over time, manufacturers and commercial sectors adopted specific barrel sizes for consistency. Today, the US barrel appears in brewing, winemaking, certain agricultural commodities, and historical documents describing early American commerce. Its varied legacy makes it a fascinating example of an evolving unit shaped by economic necessity and craftsmanship.