Approximate Practical Equivalents

APPROXIMATE PRACTICAL EQUIVALENTS
The listing of approximate practical equivalents is
included to aid the practitioner in calculating and
converting dosages among the various systems.
WEIGHT EQUIVALENTS
1 grain (gr) = 65 milligrams (mg) 1 ounce apothecary () = 31.1 grams (g)
1 milligram (mg) = 0.015 grains (gr) 1 pound
 avoirdupois (lb)
= 454 grams (g)
1 gram (g) = 15.432 grains (gr) 1 pound
 avoirdupois (lb)
= 0.45 kilograms (kg)
1 gram (g) = 0.035 ounces (oz) 1 kilogram (kg) = 2.2 pounds
 avoirdupois (lb)
1 ounce
 
avoirdupois (oz)
= 28.35 grams (g)  
VOLUME EQUIVALENTS
1 milliliter (mL) = 16.23 minims () 1 pint (pt or or Oct) = 473 milliliter (mL)
1 cubic centimeter*
 (cc)
= 1.0 milliliter (mL) 1 quart (qt) = 946 milliliter (mL)
1 fluidram† (fl ʒ) = 3.7 milliliter (mL) 1 liter (L) = 33.8 fluid ounces (fl )
1 teaspoonful† (tsp) = 5 milliliter (mL) 1 gallon (gal or C or cong) = 3785 milliliter (mL)
1 tablespoonful (tbsp) = 15 milliliter (mL) 1 milliliter (mL) = 20 drops
1 fluid ounce (fl ) = 29.57 milliliter (mL)
WEIGHT TO VOLUME EQUIVALENTS
1 milligram per
 
deciliter (mg/dL)
= 10 micrograms per milliliter (μ/mL) 1% solution = 10 milligram per milliliter (mg/mL)
1 milligram per
 
deciliter (mg/dL)
= 1 milligram percent (mg %) 1 part per million (ppm) = 1 milligram per liter (mg/L)
LINEAR EQUIVALENTS
1 millimeter (mm) = 0.04 inches (in) 1 meter (m) = 39.37 inches (in)
1 inch (in) = 25.4 millimeters (mm) 1 inch (in) = 0.025 meters (m)
1 inch (in) = 2.54 centimeters (cm)  

*Cubic centimeter and milliliter are equivalent.
†On prescription, a fluidram is assumed to contain a teaspoonful, which is 5 mL.

(Rev. 6/2018)