Understanding Carats to Grains Conversion
The metric carat (ct) is a unit of mass equal to exactly 200 milligrams, used worldwide to weigh gemstones and pearls. The grain (gr) is an old imperial mass unit equal to 64.79891 mg, still used to specify bullet and gunpowder masses. This conversion bridges the gemstone world, where mass is quoted in carats, and the firearms and pharmacology traditions that still count in grains.
Conversion Formula
To convert carats to grains, multiply by this factor:
Step-by-Step Example
Convert 25 carats to grains.
How to Convert Carats to Grains
Convert any carats value into grains in three quick steps.
- Note the carat weight: Take the gemstone or parcel mass in carats (ct).
- Multiply by the factor: Multiply the carat figure by 3.086472 to convert into grains.
- State the result: The product is the equivalent mass in grains (gr).
For example, 25 carats equals 77.1618 gr.
Carats to Grains conversion table
| Carats (ct) | Grains (gr) |
|---|---|
| 0 | 0 |
| 1 | 3.086472 |
| 2 | 6.172943 |
| 3 | 9.259415 |
| 4 | 12.34589 |
| 5 | 15.43236 |
| 6 | 18.51883 |
| 7 | 21.6053 |
| 8 | 24.69177 |
| 9 | 27.77825 |
| 10 | 30.86472 |
| 15 | 46.29708 |
| 20 | 61.72943 |
| 25 | 77.16179 |
| 30 | 92.59415 |
| 40 | 123.4589 |
| 50 | 154.3236 |
| 60 | 185.1883 |
| 70 | 216.053 |
| 80 | 246.9177 |
| 90 | 277.7825 |
| 100 | 308.6472 |
| 150 | 462.9708 |
| 200 | 617.2943 |
| 250 | 771.6179 |
| 300 | 925.9415 |
| 400 | 1234.589 |
| 500 | 1543.236 |
| 600 | 1851.883 |
| 700 | 2160.53 |
| 800 | 2469.177 |
| 900 | 2777.825 |
| 1000 | 3086.472 |
| 2000 | 6172.943 |
| 3000 | 9259.415 |
| 4000 | 12345.89 |
| 5000 | 15432.36 |
| 10000 | 30864.72 |
| 25000 | 77161.79 |
| 50000 | 154323.6 |
| 100000 | 308647.2 |
| 250000 | 771617.9 |
| 500000 | 1543236 |
| 1000000 | 3086472 |
What is the Carat?
The carat is a unit of mass used to weigh gemstones and pearls. It should not be confused with the "karat," which measures gold purity.
Definition
The metric carat is defined as exactly 200 milligrams:
That is, 1 carat = 200 mg = 0.2 g exactly. Each carat is further divided into 100 "points," so a 0.25 ct stone is called a 25-point diamond.
Origin and History
The word derives from the carob seed (Greek keration), historically used as a counterweight in balancing scales because its mass was thought to be remarkably consistent. To end regional variation, the metric carat of exactly 200 mg was adopted internationally in the early 20th century, around 1907–1914.
Law and Notable Facts
The metric carat is legally recognized in most countries for the gem trade. A common misconception is that carat measures a diamond's size; it actually measures mass, so two stones of equal carat can look different depending on cut and shape.
Real-World Examples and Conversions
A typical engagement-ring diamond is around 1 carat (200 mg). The Hope Diamond weighs about 45.52 carats (≈9.10 g). Five carats equal exactly one gram.
What is the Grain?
The grain is a small unit of mass in the avoirdupois, troy, and apothecaries' systems. Today it is used mainly for bullets, gunpowder, arrows, and some medications.
Definition
The grain is defined as exactly 1/7000 of an avoirdupois pound:
Precisely, 1 grain = 64.79891 mg exactly. There are 7000 grains in an avoirdupois pound and 480 grains in a troy ounce, making the grain the common link between the troy, avoirdupois, and apothecaries' systems.
Origin and History
The grain originally referred to the mass of a single seed of a cereal grain such as wheat or barley. It is one of the oldest units of mass in the English-speaking world and long served as the base unit from which pounds and ounces were built.
Law and Notable Facts
The grain is the only mass unit shared identically across the troy, avoirdupois, and apothecaries' systems. In firearms, ammunition is still specified in grains—for both projectile mass and powder charge.
Real-World Examples and Conversions
A common 9mm bullet weighs about 115 grains (≈7.45 g). A standard aspirin tablet of 325 mg is roughly 5 grains. One gram equals about 15.43 grains.
Frequently Asked Questions
What is a carat?
A metric carat is exactly 200 milligrams, the international standard for weighing gemstones and pearls; it is unrelated to karat, which measures gold purity.
How many grains are in one carat?
One carat equals 3.086472 grains, since a carat is 200 mg and a grain is 64.79891 mg.
Is the gemstone carat related to the shooting grain?
No, they belong to different systems entirely; the shared conversion simply lets you compare a 200 mg carat against the 64.79891 mg grain.
How do I convert carats to grains?
Multiply the carat value by 3.086472 to obtain grains.
People also convert
Complete Carats conversion table
| Unit | Result |
|---|---|
| Micrograms (mcg) | 200000 mcg |
| Milligrams (mg) | 200 mg |
| Grams (g) | 0.2 g |
| Kilograms (kg) | 0.0002 kg |
| Metric Tonnes (mt) | 2e-7 mt |
| Ounces (oz) | 0.007054792 oz |
| Pounds (lb) | 0.0004409245 lb |
| Stones (st) | 0.00003149461 st |
| Tons (t) | 2.204623e-7 t |
| Long Tons (long-ton) | 1.968413e-7 long-ton |
| Troy Ounces (ozt) | 0.006430149 ozt |
| Grains (gr) | 3.086472 gr |
| US Hundredweights (cwt-us) | 0.000004409245 cwt-us |
| UK Hundredweights (cwt-uk) | 0.000003936826 cwt-uk |
| Slugs (slug) | 0.00001370435 slug |