Convert Apothecary Ounces to Kilograms
Convert Apothecary Ounces (oz ap) to Kilograms (kg) instantly and accurately.
Conversion Formula
kg = oz ap × 0.0311034768
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 Although the apothecary system has been replaced by SI units in modern medicine, the apothecary ounce still appears in historical pharmacopeias, traditional herbal medicine texts, and some compounding pharmacy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 Kilograms
The kilogram (kg) is the SI base unit of mass - the fundamental unit from which all other mass measurements in the metric system are derived. Since 2019 it has been defined by fixing the Planck constant h to exactly 6.62607015 × 10⁻³⁴ J·s, replacing the 130-year-old International Prototype Kilogram (a platinum-iridium cylinder kept in Sèvres, France). The kilogram governs daily life worldwide: body weight in most countries, grocery shopping, luggage allowances, postal rates, freight pricing, and ingredient quantities in cooking all reference kilograms.
Quick Reference Table
| Apothecary Ounces (oz ap) | Kilograms (kg) |
|---|---|
| 1 oz ap | 0.0311035 kg |
| 2 oz ap | 0.062207 kg |
| 5 oz ap | 0.155517 kg |
| 10 oz ap | 0.311035 kg |
| 25 oz ap | 0.777587 kg |
| 50 oz ap | 1.55517 kg |
| 100 oz ap | 3.11035 kg |