Dram (unit)

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A dram , also known as a drachm (especially in British English), is a unit of mass , a so-called trade weight . It is mainly used in England and North America . It is also used as a volume unit .

There are two different units with this designation:

  • Dram ( avoirdupois ), the actual dram (unit symbols: dr. Av. Or dr.)
  • Dram , Drachm ( apothecarius ; troy ) (unit symbols: dr. Ap. Or dr. Tr., As symbols ʒ or ℨ)

Similar to the Armenian Dram of the same name, the word comes from the ancient Greek drachma .

Dram (avoirdupois)

Physical unit
Unit name Dram (avoirdupois)
Unit symbol ,
Physical quantity (s) Dimensions
Formula symbol
system Anglo-American system of measurement
In SI units

The dram ( avoirdupois ) is a non-SI-compliant unit of mass. The bracketed part of the name is intended to indicate that it belongs to the Avoirdupois system of measurement ( English : avoirdupois [weight] ; old French : aveir de pois = "goods of weight").

The dram ( avoirdupois ) corresponds to one of a trading pound . One trading pound (avoirdupois) is equivalent to just under 454 grams (more precisely 453.592 37 g, since 1959). Thus, 453.59 grams (1 pound av.) Divided by 256 (drams av.) Would be approximately 1.77 grams (metric grams).


1 dr. av. = 1 dr. = 27.34375  gr. ≈ 1.772  g
lb. = 16  oz. = 256 dr. = 7000  gr.

Dram equivalent as the load weight for shotgun cartridges

The Dram Equivalent , given in the measure "Drams av.", Is still used in the English-speaking world as a unit of measurement for gunpowder loads of shotgun ammunition . What is meant here is the roughly equivalent (equivalent) performance of a (smaller) amount of today's charges of nitro powder to a (larger) amount of older, weaker gunpowder (coll. "Black powder"). This is to be understood as "the weight of modern powder in X ounces (or grams) for this cartridge charge, for approximately the same power (gas pressure, muzzle velocity), corresponds to approximately Y dram of older gunpowder".

Dram (apothecarius) / Dram (troy)

Physical unit
Unit name Dram (troy; apothecarius)
Unit symbol ,
Physical quantity (s) Dimensions
Formula symbol
system Anglo-American system of measurement
In SI units
Named after Troyes

Dram ( apothecarius ) and dram ( troy ) denote a non-SI-compliant unit of mass. Both are alternatively referred to as drachm (also: drachme ). They are mainly still used in England , the Netherlands and the USA .

The name Dram ( troy ) goes back to the French city of Troyes . The measure is used to determine the weight of precious metals and in coinage, but also for medicinal recipes and scientific determinations. Hence the alternative designation as Dram ( apothecarius ), through its use as part of the pharmacist's weight measurement system widespread in Europe (derived from the profession of pharmacist , Middle Latin apothecarius ).

The dram ( troy ) in the Troy or apothecary's system of measurement ( troy weight ) corresponds to 60 times a grain . While a trading pound equals 7000 grains, the medicinal pound (troy; apothecarius) is fixed at 5760 grains . A dram / drachm ( ap .; tr. ) Is thus one of a medicinal pound. This results in 60 grains (would be 1 dram ap .; dr.) Multiplied by 96 (number of drams per pound ap .; dr.) A total of 5760 grains.

An English medicinal pound is a little over 373 grams (more precisely 373.241 721 6 g, since 1959). Thus, 373.24 g (1 pound ap .; tr.) Divided by 96 (drams ap .; tr.) Would be approximately 3.89 g (metric grams).


1 dr. ap. = 1 dr. tr. = 3  s. ap. = 60  gr. ≈ 3.888  g
lb. ap. = 12  oz .ap. = 96 dr. ap. = 288  s. ap. = 5760  gr.

Comparison of Dram and Drachm

384 dr. av. = 384 dr. = 175 dr. ap. = 175 dr. tr. = 1.5  lb.

Dram (m) as trade weight in other regions

The measure of Dram (m) was also used as a Bulgarian and Turkish commercial weight, and it was converted into equivalent

  • 1 dram (m) = 3.2 grams

In Egypt the measure was converted as

  • 1 dramm dirhem = 3.1 grams

The dram as a unit of volume

The liquid dram (fluid dram, fluid drachm; abbreviated with fl dr, ƒ 3 or fʒ) is defined as ⅛ of a "liquid ounce" ( fluid ounce ). This corresponds exactly to:

  • 3,696 691 195 312 5  ml in the United States of America and
  • 3.551 632 812 500 0 ml in the Commonwealth of Nations and Ireland.

In the UK, a teaspoon was previously defined as 1 ½ liquid drams (just over 5 ml).

The dram is also used colloquially to mean sip (a small drink), especially in connection with Scottish whiskey . It should be noted that this “dram” can also be 10 regular liquid drams, for example, a well-filled shot glass full (approx. 3.5 cl).

See also

Individual evidence

  1. "Dram Equivalent", Definition _ Merriam-Webster.com Dictionary (English)
  2. Peter Kurzweil: The Vieweg unit lexicon: formulas and terms from physics, chemistry and technology. Springer-Verlag, 2013, ISBN 978-3-32292-920-4 , p. 105.