Convert Ton Register (ton reg) to Dram (dr) 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.
Dram (dr)
The fluid dram is a small historical unit equal to 1/8 of a US fluid ounce or 3.6967 mL (US), with slightly different imperial values. It originated in apothecaries and early pharmaceutical texts, where drams measured potent liquid medicines, tinctures, and extracts. In daily life, drams appeared in old cocktail recipes, medicinal syrups, and household remedies. However, the inconsistency between US and UK drams, along with the rise of the metric system, pushed it out of modern use. Today, the dram survives mostly in whiskey culture—where a "dram" informally means a small pour, not a precise measurement—and in historical studies of medicine.