A metric carat is exactly 200 milligrams.
Carats to Grains Converter — ct to gr
Convert Carat (ct) to Grain (gr) using the exact conversion factor (1 carat = 3.086471671 grain). See the formula, worked examples, and conversion table.
Carats to Grains 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 grain is exactly 64.79891 milligrams.
Result = input x 0.0002 / 6.479891e-5.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Carats to Grains
Weight conversions between Carat and Grain 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 metric carat is exactly 200 milligrams, and a grain is exactly 64.79891 milligrams.
Formula
grains = carats × 3.08647167059
This factor comes from each unit's defined relationship to the category's base unit: 1 carat equals 0.0002 base units, and 1 grain equals 0.00006479891 base units, so dividing one by the other gives the direct carat-to-grain factor of 3.08647167059.
Simple example
1 ct × 3.086471671 = 3.086471671 gr
1 carat = 3.086471671 grains.
Real-world example
50 ct × 3.086471671 = 154.3235835 gr
50 carats = 154.3235835 grains.
Conversion table
| Carat (ct) | Grain (gr) |
|---|---|
| 1 ct | 3.086471671 gr |
| 5 ct | 15.43235835 gr |
| 10 ct | 30.86471671 gr |
| 25 ct | 77.16179176 gr |
| 50 ct | 154.3235835 gr |
| 100 ct | 308.6471671 gr |
Reverse conversion: Grain to Carat
3.086471671 gr × 0.32399455 = 1 ct
3.086471671 grains = 1 carats.
carats = grains × 0.32399455
For a page dedicated to this direction, see Grain to Carat.
Understanding the Carat (ct)
A metric carat is exactly 200 milligrams.
Understanding the Grain (gr)
A grain is exactly 64.79891 milligrams.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grains are in 1 carat?
1 carat equals 3.086471671 grains, using the exact defined conversion factor rather than an estimate.
How do I convert carat to grain?
Multiply the carat value by 3.086471671. The converter above does this instantly to whatever precision you set.
How do I convert grain back to carat?
Use the reverse factor: 1 grain equals 0.32399455 carats. You can also use the swap control in the converter above to flip the direction instantly.
What is a carat?
Carat (ct) is a unit of mass/weight.
What is a grain?
Grain (gr) is a unit of mass/weight.
Is the carat to grain conversion exact?
Yes. Both carat and grain are defined by fixed standards rather than physical artifacts, so the factor of 3.086471671 used above is exact to as many digits as you choose to display.