Convert Milligrams to Apothecary Ounces

Convert Milligrams (mg) to Apothecary Ounces (oz ap) instantly and accurately.

Milligrams (mg)
Apothecary Ounces (oz ap)

Conversion Formula

oz ap = mg × 3.215074657e-5

About Milligrams

A milligram (mg) is one thousandth of a gram (10⁻³ g). It is the primary unit for pharmaceutical dosing: aspirin tablets are typically 500 mg, ibuprofen 200-400 mg, and melatonin supplements 0.5-10 mg. Precious metal assay results and alloy compositions are specified in milligrams per kilogram (mg/kg = ppm). Nutritional labels worldwide list mineral content in milligrams - the recommended daily intake of iron is 8-18 mg, calcium 1000 mg, and sodium under 2300 mg. A grain of rice weighs about 25-30 mg, and a medium eyelash approximately 0.1 mg.

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 Although the apothecary system has been replaced by SI units in modern medicine, the apothecary ounce still appears in historical pharmacopeias, traditional herbal medicine texts, and some compounding pharmacy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.

Quick Reference Table

Milligrams (mg)Apothecary Ounces (oz ap)
1 mg3.215 × 10-5 oz ap
2 mg6.43 × 10-5 oz ap
5 mg0.000160754 oz ap
10 mg0.000321507 oz ap
25 mg0.000803769 oz ap
50 mg0.00160754 oz ap
100 mg0.00321507 oz ap

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