Convert Apothecary Ounces to Grains
Convert Apothecary Ounces (oz ap) to Grains (gr) instantly and accurately.
Conversion Formula
gr = oz ap × 480
About Apothecary Ounces
An apothecary ounce (oz ap) is identical in mass to the troy ounce - approximately 31.10 grams - and equals 8 apothecary drams or 480 grains. It was the standard ounce used by pharmacists and physicians across Europe and North America from medieval times until the 20th century. Although the apothecary system has been replaced by SI units in modern medicine, the apothecary ounce still appears in historical pharmacopeias, traditional herbal medicine texts, and some compounding pharmacy references.
About Grains
A grain (gr) is the smallest unit in both the avoirdupois and troy weight systems, equal to exactly 64.79891 milligrams. Originally defined as the mass of a single grain of barley or wheat from the middle of an ear, it has been a standard of weight since ancient times. Today, grains are used to weigh gunpowder charges and bullets (a standard .308 rifle bullet weighs 168 gr), pharmaceutical preparations in apothecary compounding, and the fineness of gold alloys. Arrowhead and fishing hook weights are also specified in grains.
Quick Reference Table
| Apothecary Ounces (oz ap) | Grains (gr) |
|---|---|
| 1 oz ap | 480 gr |
| 2 oz ap | 960 gr |
| 5 oz ap | 2400 gr |
| 10 oz ap | 4800 gr |
| 25 oz ap | 12000 gr |
| 50 oz ap | 24000 gr |
| 100 oz ap | 48000 gr |