Convert Grain to Stone (gr → st)

Converting grains to stones is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in grains

   Start with the number of grains (gr) you want to convert.
2. 2
   Multiply by 0.0000102

   The conversion factor from gr to st is 0.0000102. Multiply your value by this number.
3. 3
   Read the result in stones

   The result is your value in stones (st).

Multiply the value in grains by 0.0000102. For the reverse direction, multiply by 98,000.

• ✓1 grain = 64.79891 mg exactly. 7000 grains = 1 pound.
• ✓Ballistics is one of the few modern contexts where grains are essential.
• ✓Some older pharmacology dosing survives in grain units — 5 gr ≈ 325 mg.

• ✗Confusing the grain (mass) with the troy grain in older precious-metal contexts — they are identical (64.8 mg).
• ✗Assuming "grain" refers to an amount of cereal — in firearms it is always a weight.
• ✗Reading "5 gr" as 5 grams — it is 5 grains (324 mg).

What is the Grain?

The grain equals exactly 64.79891 milligrams (0.06479891 g) and is the smallest unit in the traditional avoirdupois weight system. Originally based on the average mass of a single grain of wheat or barley, the unit was standardized to its current value with the 1959 international yard and pound agreement. The grain is still used in pharmaceutical compounding (some older drug formulations specify grains, especially aspirin and codeine), arrow tips and ammunition (bullet weights are commonly given in grains — a 9 mm bullet is around 115 grains), and precious-metal weighing (one troy ounce = 480 grains). It relates to the ounce (437.5 grains = 1 oz avoirdupois), the pound (7,000 grains = 1 lb), and the milligram (1 grain ≈ 64.8 mg). The unit reflects medieval agriculture's role in shaping early measurement systems.

• Bullet and gunpowder mass in ballistics
• Older pharmaceutical dosing in Anglo-Saxon countries
• Arrow shaft and archery equipment weights

What is the Stone?

The stone equals exactly 14 pounds or 6.35029318 kilograms and remains the traditional British unit for personal body weight. Originally based on a stone literally used as a counterweight on a balance scale, the unit was standardized at 14 pounds by an Act of Parliament in 1835. While metrication has reduced its role in commerce, the stone persists in British everyday life — a person is described as '11 stone 4' (158 lb) rather than 72 kg — and is widely used in British and Irish weight-loss programs, medical contexts, and gym equipment. The stone is virtually unknown in the United States and most of the world. It relates to the pound (14 lb = 1 stone), the kilogram (1 stone ≈ 6.35 kg), and the long ton (160 stone = 1 long ton). Stones-and-pounds notation (like '11 st 4 lb') is the British equivalent of decimal kilograms.

• Human body weight in the UK and Ireland
• British medical charts and patient records
• British boxing and wrestling press reports