Convert Apothecary Ounces to Pennyweights
Convert Apothecary Ounces (oz ap) to Pennyweights (dwt) instantly and accurately.
Conversion Formula
dwt = oz ap × 20
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 Although the apothecary system has been replaced by SI units in modern medicine, the apothecary ounce still appears in historical pharmacopeias, traditional herbal medicine texts, and some compounding pharmacy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 Pennyweights
A pennyweight (dwt or pwt) equals 24 grains or 1/20 of a troy ounce - approximately 1.555 grams. Its name derives from the weight of an English silver penny in the medieval period. Pennyweights are the standard unit used by jewellers and goldsmiths in North America for weighing precious metals: gold, silver, and platinum. When a jeweller quotes the gold weight of a ring or chain, they typically use pennyweights. Gold buyers, refiners, and scrap metal dealers quote prices per pennyweight (often abbreviated 'DWT') when appraising jewellery.
Quick Reference Table
| Apothecary Ounces (oz ap) | Pennyweights (dwt) |
|---|---|
| 1 oz ap | 20 dwt |
| 2 oz ap | 40 dwt |
| 5 oz ap | 100 dwt |
| 10 oz ap | 200 dwt |
| 25 oz ap | 500 dwt |
| 50 oz ap | 1000 dwt |
| 100 oz ap | 2000 dwt |