A grain is exactly 64.79891 milligrams.
Grains to Stones Converter — gr to st
Convert Grain (gr) to Stone (st) using the exact conversion factor (1 grain = 0.0000102041 stone). See the formula, worked examples, conversion table, history, and common uses.
Grains to Stones converter
Converter
Mass/Weight Converter
Convert SI mass, imperial weight, jewelry, atomic, and astronomy mass units.
Context values
Some unit families need one extra value for a physically accurate result.
A stone is 14 pounds.
Result = input x 6.479891e-5 / 6.35029318.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Grains to Stones
Weight conversions between Grain and Stone come up constantly in everyday commerce, shipping, and cooking, since US packaging is usually labeled in pounds while most of the rest of the world uses kilograms. Specifically: A grain is exactly 64.79891 milligrams, and a stone is 14 pounds.
Formula
stones = grains × 0.0000102040816327
This factor comes from each unit's defined relationship to the category's base unit: 1 grain equals 0.00006479891 base units, and 1 stone equals 6.35029318 base units, so dividing one by the other gives the direct grain-to-stone factor of 0.0000102040816327.
Simple example
1 gr × 0.00001020408163 = 0.0000102041 st
1 grain = 0.0000102041 stones.
Real-world example
50 gr × 0.00001020408163 = 0.0005102041 st
50 grains = 0.0005102041 stones.
Conversion table
| Grain (gr) | Stone (st) |
|---|---|
| 1 gr | 0.0000102041 st |
| 5 gr | 0.0000510204 st |
| 10 gr | 0.0001020408 st |
| 25 gr | 0.000255102 st |
| 50 gr | 0.0005102041 st |
| 100 gr | 0.0010204082 st |
Reverse conversion: Stone to Grain
0.0000102041 st × 98000 = 1.0000018 gr
0.0000102041 stones = 1.0000018 grains.
grains = stones × 98000
For a page dedicated to this direction, see Stone to Grain.
Understanding the Grain (gr)
A grain is exactly 64.79891 milligrams.
Understanding the Stone
Stone (st) measures mass. A stone is 14 pounds: exactly 6.35029318 kilograms. It is classified as a UK customary unit.
Where it's used: United Kingdom and Ireland (body weight)
Uses of the Stone today
- Body weight reporting in the UK and Ireland (e.g. '12 stone 5 pounds')
- Historical wool and agricultural produce weighing
History of the Stone
The stone dates to medieval England as a general-purpose weight unit, historically varying by region and commodity (a 'stone' of wool differed from a 'stone' of meat) before settling on 14 pounds for general use. It remains in everyday use for body weight in the UK and Ireland, unlike most other English customary units which have been replaced or supplemented by metric measures.
Historical origin. Stone was not the invention of a single named person; it developed through the process described above.
Stone — sources
- UK Weights and Measures Act 1985 — Confirms the stone (14 lb) as a legally recognized UK unit for body weight.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many stones are in 1 grain?
1 grain equals 0.0000102041 stones, using the exact defined conversion factor rather than an estimate.
How do I convert grain to stone?
Multiply the grain value by 0.00001020408163. The converter above does this instantly to whatever precision you set.
How do I convert stone back to grain?
Use the reverse factor: 1 stone equals 98,000 grains. You can also use the swap control in the converter above to flip the direction instantly.
What is a grain?
Grain (gr) is a unit of mass/weight.
What is a stone?
Stone (st) measures mass. A stone is 14 pounds: exactly 6.35029318 kilograms. It is classified as a UK customary unit.
Is the grain to stone conversion exact?
Yes. A stone is 14 pounds: exactly 6.35029318 kilograms. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.