Convert Apothecary Ounces to Avoirdupois Drams
Convert Apothecary Ounces (oz ap) to Avoirdupois Drams (dr av) instantly and accurately.
Conversion Formula
dr av = oz ap × 17.55428571
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 Although the apothecary system has been replaced by SI units in modern medicine, the apothecary ounce still appears in historical pharmacopeias, traditional herbal medicine texts, and some compounding pharmacy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 Avoirdupois Drams
An avoirdupois dram (dr av) is 1/16 of an avoirdupois ounce - approximately 1.772 grams. Part of the avoirdupois system that governs everyday trade weights in the UK and US, it was historically used to measure small quantities of goods and spices in commerce. While rarely used in modern commerce (having been replaced by grams in most applications), the avoirdupois dram still appears in some spice and herbalist contexts, in US gunpowder loading data (where charges are specified in grains and drams), and in archaic recipe books.
Quick Reference Table
| Apothecary Ounces (oz ap) | Avoirdupois Drams (dr av) |
|---|---|
| 1 oz ap | 17.5543 dr av |
| 2 oz ap | 35.1086 dr av |
| 5 oz ap | 87.7714 dr av |
| 10 oz ap | 175.543 dr av |
| 25 oz ap | 438.857 dr av |
| 50 oz ap | 877.714 dr av |
| 100 oz ap | 1755.43 dr av |