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Grain Conversion Table
This comprehensive grain conversion table shows how various units relate to grains. Use this reference for quick conversions between grains and other common mass/weight units.
| Conversion | To Unit | Multiplier |
|---|---|---|
| Grains to kilograms | Kilograms | 0.00006479891 |
| Grains to grams | Grams | 0.06479891 |
| Grains to milligrams | Milligrams | 64.79891 |
| Grains to micrograms | Micrograms | 64798.91 |
| Grains to tonnes | Tonnes | 6.479891e-8 |
| Grains to carats | Carats | 0.32399455 |
| Grains to pounds | Pounds | 0.000142857 |
| Grains to ounces | Ounces | 0.002285714 |
| Grains to stones | Stones | 0.000010204 |
| Grains to hundredweights | Hundredweights | 0.000001429 |
| Grains to slugs | Slugs | 0.00000444 |
This grain conversion reference table provides accurate conversion factors for both metric (SI) units and imperial units. All values are based on internationally recognized standards for maximum precision in scientific and engineering applications.
What is a Grain?
The grain (symbol: gr) is a unit of mass that is equal to exactly 64.79891 milligrams. Historically, it was based on the mass of a single grain of wheat or barley. The grain is part of the avoirdupois system of weights, which is a system of weights commonly used in the United States and United Kingdom. It is still used today in measuring the mass of bullets, arrows, and sometimes medication dosages. Our grain conversion tool helps you easily convert between grains and other units. For example, 1 grain equals approximately 0.0648 grams or 0.0023 ounces.
What is the SI of Grain?
The grain is not an SI unit, but it can be converted to the SI base unit for mass, the kilogram. In the metric system, 1 grain is equal to 0.00006479891 kilograms. While not part of the International System of Units (SI), it is still used in specialized applications and can be accurately converted using our SI units conversion tools:
- Kilogram (kg) = 64.79891 milligrams
- Gram (g) = 0.06479891 grams
- Milligram (mg) = 64.79891 milligrams
- Microgram (µg) = 64798.91 micrograms
- Tonne (t) = 0.00000006479891 tonnes
What are Grains Used For?
Grains are used in a variety of specialized applications, particularly where very small mass measurements are required. As a traditional unit, grains provide a standard for specific industries that still use imperial measurements:
Bullet Weights
Firearms and ammunition specifications. For example, a .22 caliber bullet might weigh 40 grains, while a larger rifle bullet could weigh 180 grains.
Archery
Arrow weights and broadhead measurements. For example, hunting arrows typically range from 300 to 500 grains in total weight.
Pharmaceuticals
Historically used for medication dosages and still referenced in some traditional prescriptions. For example, a typical aspirin tablet might contain 325 milligrams or about 5 grains.
Jewelry
Occasionally used for measuring small gemstones and precious metals in traditional or specialized contexts. For example, a small diamond might weigh 20 grains (approximately 1.3 carats).
Etymology and History
The grain is one of the oldest units of mass, dating back to ancient civilizations. It was originally based on the average mass of a single grain of wheat or barley. This made it a convenient and relatively consistent unit for trade in agricultural societies. The grain was later standardized in the avoirdupois system, which became the common system of weights in England. In 1959, the grain was precisely defined as exactly 64.79891 milligrams, making it one of the few traditional units with an exact metric equivalent. This definition ensures consistency with the metric system while preserving the grain's historical significance.
Despite the widespread adoption of metric units, the grain remains in use in specific applications where its small size is convenient or where tradition dictates its use. Its precise definition allows for accurate conversions to SI units, making it compatible with modern measurement systems while maintaining its historical roots.
Frequently Asked Questions
Why is the grain still used today?
The grain is still used today primarily in specialized applications like ammunition and archery where its small size is convenient for measurement. Its historical significance and precise definition make it suitable for these niche applications where traditional units are preferred or required. The grain's exact metric equivalent (64.79891 mg) ensures that it can be accurately converted to modern SI units when needed.
How accurate is the grain definition?
The grain is defined as exactly 64.79891 milligrams, making it one of the most precisely defined traditional units. This exact definition allows for conversions to SI units with complete accuracy, ensuring consistent measurements across different systems. This precision is particularly important in applications like bullet weights where accuracy is crucial.
How do I convert grains to other units?
Use our grain conversion calculators above, or multiply by the appropriate conversion factor. For example, to convert grains to grams, multiply by 0.06479891; to convert grains to milligrams, multiply by 64.79891. For detailed instructions on converting grains to kilograms, visit our grain to kg converter. Our tool also handles conversions to imperial units like pounds and ounces with high precision.
What are common uses for grain conversion?
Grain conversion is essential in ammunition manufacturing (bullet weights), archery (arrow weights), pharmaceuticals (medication dosages), and jewelry (gemstone weights). Whether calculating the weight of a hunting bullet or determining medication dosage, our grain converter tool simplifies these specialized tasks. It's also useful for historical research and antique measurements.
How does grain conversion differ from other mass units?
The grain is a traditional unit with a very small value (1 grain = 64.79891 mg), making it particularly useful for measuring small masses. Unlike other traditional units, it has an exact metric definition, making conversions to SI units straightforward. This relationship makes grain conversion particularly precise compared to other traditional units without exact metric equivalents.
Can I convert very small or very large measurements in grains?
Yes, our grain converter handles both extremely small and large measurements with precision. For very small measurements, you might work directly in grains. For large masses, convert grains to kilograms or tonnes (1,000,000 grains ≈ 64.8 kg). Our smart rounding feature ensures readable results for all scales.
Is your grain conversion tool free to use?
Yes, our grain conversion calculator is completely free with no registration required. Simply enter your value, select your target unit, and get instant, accurate results. We believe precise measurement conversion should be accessible to everyone, from hobbyists reloading ammunition to professionals working on specialized engineering projects.