Grain (gr)
The grain (gr) is exactly 64.79891 mg. It is identical in the avoirdupois, troy and apothecaries systems.
Symbol: gr
Quantity: mass (commonly called weight)
SI relation: 1 gr = 0.00006479891 kg (exact)
Derivation: 1 gr = 1/7000 lb = 64.79891 mg (exact)
Exact: yes, by definition
Reference conditions. Avoirdupois system: 1 lb = 16 oz = 7000 grains = 0.45359237 kg exactly (1959 agreement).
Typical uses
- Bullet and powder weights
- Moisture content of air (grains of water per pound of dry air)
- Older pharmacy doses (aspirin 5 gr = 325 mg)
Convert grains to other units
| Conversion | 1 gr equals | Reverse |
|---|---|---|
| grain to kilogram | 0.00006479891 kg | kilogram to grain |
| grain to gram | 0.06479891 g | gram to grain |
| grain to milligram | 64.79891 mg | milligram to grain |
| grain to pound | 0.0001428571429 lb | pound to grain |
| grain to ounce | 0.002285714286 oz | ounce to grain |
| grain to microgram | 64798.91 µg | microgram to grain |
| grain to metric ton | 6.479891 × 10⁻⁸ t | metric ton to grain |
| grain to stone | 0.00001020408163 st | stone to grain |
| grain to short ton | 7.142857143 × 10⁻⁸ ton (US) | short ton to grain |
| grain to troy ounce | 0.002083333333 oz t | troy ounce to grain |
| grain to long ton | 6.37755102 × 10⁻⁸ ton (UK) | long ton to grain |
| grain to carat | 0.32399455 ct | carat to grain |
Open the Weight and Mass Converter to convert any value between all units.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "grain (gr)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Grain (gr). Retrieved October 17, 2026, from https://scientificconverters.com/units/grain/
IEEE
Scientific Converters, "Grain (gr)," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/grain/