Apothecary Units Converter
Convert between old apothecary weight units (grains, scruples, drams, ounces, pounds) and modern metric units.
Frequently asked questions
Is this tool free?
Yes. Calchemy tools are free to use in your browser.
Is my data uploaded?
No. The tools are designed to run locally in your browser unless clearly stated otherwise.
Were these real units?
Yes. The apothecary system (grains, scruples, drams, ounces and pounds) was genuinely used by pharmacists and alchemists for dosing medicines for centuries, and traces of it survive in the grain unit still used for gunpowder and archery bow draw weights today.
Why don't the ounce and pound match the ones I know?
Apothecary ounces and pounds are slightly different from avoirdupois (everyday) ounces and pounds, which is exactly the kind of confusion that eventually pushed medicine towards the metric system.