Apothecaries' Weight System

Apothecaries' fluid and weight system with ounces, drachms, grains, scruples and more.

UnitEquivalentIn GrainsIn Minims (Fluid)
Pound (Weight)12 ounces5760-
Ounce (Weight)8 drachms480-
Drachm (Weight)3 scruples60-
Scruple (Weight)1 scruple20-
Grain1 grain1-
Fluid Ounce (U.S.)8 drachms-480
Fluid Drachm1 drachm-60
Minim (Fluid)1 minim-1

Conversion Factors

Apothecaries' Weight

  • 1 pound = 12 ounces = 5760 grains
  • 1 ounce = 8 drachms = 480 grains
  • 1 drachm = 3 scruples = 60 grains
  • 1 scruple = 20 grains

Apothecaries' Fluid Measure

  • 1 U.S. fluid ounce = 8 drachms = 1.805 cubic inch = 1/128 U.S. gallon
  • 1 fluid drachm = 60 minims
  • 1 British fluid ounce = 1.732 cubic inch