Apothecaries' Drams to Kilograms (ʒ to kg)

1 apothecaries' dram equals 0.0038879346 kilograms exactly.

1 apothecaries' dram = 0.0038879346 kilograms

How to convert apothecaries' drams to kilograms

To convert apothecaries' drams to kilograms, multiply the number of apothecaries' drams by 0.0038879346. This factor is exact. To go the other way, multiply kilograms by 257.2059725 (rounded).

kilograms = apothecaries' drams × 0.0038879346

Example: 10 apothecaries' drams = 0.038879346 kilograms.

About these units

Apothecaries' Dram (ʒ)

Troy & apothecaries'Historical unit (no longer in standard use)

60 grains or 3 scruples (3.888 g). Used in old medical prescriptions.

Greek drachma coins left their mark on this unit, which the apothecaries' tables spelled drachm or dram and abbreviated with a curled symbol. It was worth 60 grains, or three scruples, or about 3.89 grams, and eight of them filled an apothecaries' ounce.

Doctors wrote it into Latin prescriptions with Roman numerals, so three drams appeared as the symbol followed by iij and half a dram as the symbol followed by ss, short for semis. Until about 1900 most prescriptions were written this way.

Do not confuse it with the avoirdupois dram, which is much smaller than this one, and with the fluid dram used for liquids. An Irish pharmacopoeia of 1850 even proposed an avoirdupois-based version of about 54.68 grains. British law ended the apothecaries' system in the 1970s, and modern doses are given in grams or milligrams.

1 apothecaries' dram = 0.0038879346 kilograms (exactly).

Sources: Wikipedia: Apothecaries' system; Wikipedia: Troy weight

Kilogram (kg)

Metric (SI)Current unit

The SI base unit of mass. Since 2019 it is defined by fixing the value of the Planck constant, replacing the old platinum-iridium cylinder in Paris.

Oddly for a base unit, the kilogram began life as a derived one. In 1793 revolutionary France defined the grave as the mass of one litre of water, and a decree of 1795 then replaced it with the kilogramme, a name built from the Greek khilioi (a thousand) and gramma, a Late Latin word for a small weight. In 1799 a platinum cylinder, the Kilogramme des Archives, became the physical standard, matching a cubic decimetre of water at its densest, around 4 degrees Celsius. In 1889 the metric community adopted a platinum-iridium cylinder made in 1879, the International Prototype of the Kilogram, nicknamed Le Grand K.

The kilogram is still the only SI base unit with a prefix in its name. Because SI forbids stacked prefixes, a millionth of a kilogram is a milligram rather than a microkilogram, so every mass prefix is attached to the gram. Calibrating every national standard against one object in a vault near Paris meant that all of them drifted relative to it, so in November 2018 member states voted to tie the kilogram to a fixed value of the Planck constant. The change took effect on 20 May 2019. Day to day nothing shifted, but the definition no longer depends on a single piece of metal.

The kilogram is the reference unit for weight & mass on this site.

Sources: NIST: Kilogram introduction (SI redefinition); Wikipedia: Kilogram

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