Select a category
Conversion Formula:
Convert Grain to Stone (ancient) (gr to st (ancient)) instantly with accurate, readable results.
Use our Mass Unit Converter to convert between grams, kilograms, pounds, ounces, and other weight units instantly. Designed for cooking, science, fitness, and engineering needs, this unit conversion tool offers accurate results between metric and imperial systems. Whether you’re tracking body weight, measuring ingredients, or handling heavy machinery, our mass unit conversion calculator has you covered.
Grain (gr) — a small imperial and US customary unit of mass
It is defined as exactly 1/7000 of an avoirdupois pound; since 1 lb = 0.45359237 kg exactly, 1 gr = 64.79891 mg exactly. Used mainly for measuring bullets, gunpowder, arrows, and some pharmaceutical or historical masses.
- Symbol: gr
- System: Imperial and US customary unit for mass
- Exact relations: 1 gr = 1/7000 lb = 1/437.5 oz = 64.79891 mg
- Metric equivalents: 1 gr = 0.06479891 g ≈ 0.0000647989 kg
- Typical examples: a small bullet ~40 gr; a larger rifle bullet ~150 gr; an aspirin tablet was historically 5 gr.
Stone (ancient) — a variable historical unit of mass
It was not a single fixed unit; in ancient and medieval use, a “stone” could mean a locally chosen trade weight, often varying by region, period, and commodity. Used historically for weighing goods such as wool, grain, meat, and other trade commodities, and for stone weights used as practical measuring standards.
- Symbol: stone, st
- System: Historical unit for mass; not a fixed SI or modern imperial standard in ancient use
- Common historical range: about 4 to 32 lb ≈ 1.814 to 14.515 kg, depending on context
- Modern reference point: the later British imperial stone is exactly 14 lb = 6.35029318 kg
- Typical examples: trade stones could be used for wool, grain, or livestock products; a “stone” in one market might differ from a “stone” in another; historical records should be interpreted by period and location.